diff --git a/internal/app/library_cache.go b/internal/app/library_cache.go
new file mode 100644
index 0000000..189d933
--- /dev/null
+++ b/internal/app/library_cache.go
@@ -0,0 +1,170 @@
+package app
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+type libraryCache struct {
+	Dramas     []Drama                       `json:"dramas"`
+	LoadedAt   time.Time                     `json:"loadedAt"`
+	LastError  string                        `json:"lastError,omitempty"`
+	Sources    map[string]librarySourceState `json:"sources,omitempty"`
+	HongguoApp *hongguoCatalogState          `json:"hongguoApp,omitempty"`
+}
+
+func libraryCachePath(outputDir string) string {
+	return filepath.Join(outputDir, "library.json")
+}
+
+func readLibraryCache(outputDir string) (libraryCache, error) {
+	var cache libraryCache
+	path := libraryCachePath(outputDir)
+	body, err := os.ReadFile(path)
+	if errors.Is(err, os.ErrNotExist) {
+		path = filepath.Join(outputDir, "ui-state.json")
+		body, err = os.ReadFile(path)
+	}
+	if err != nil {
+		return cache, err
+	}
+	if err := json.Unmarshal(body, &cache); err != nil {
+		return cache, fmt.Errorf("本地剧库缓存损坏 %s: %w", path, err)
+	}
+	originalCount := len(cache.Dramas)
+	cache.Dramas = onlyHongguoDramas(cache.Dramas)
+	sources := make(map[string]librarySourceState)
+	for source, state := range cache.Sources {
+		if canonicalProviderSource(source) == sourceHongguo {
+			sources[sourceHongguo] = state
+		}
+	}
+	if originalCount != len(cache.Dramas) || len(sources) != len(cache.Sources) {
+		cache.LastError = librarySourceErrors(sources)
+	}
+	cache.Sources = sources
+	return cache, nil
+}
+
+func writeLibraryCache(outputDir string, cache libraryCache) error {
+	if err := os.MkdirAll(outputDir, 0o755); err != nil {
+		return err
+	}
+	file, err := os.CreateTemp(outputDir, ".library-*.tmp")
+	if err != nil {
+		return err
+	}
+	defer os.Remove(file.Name())
+	encoder := json.NewEncoder(file)
+	if err := encoder.Encode(cache); err != nil {
+		_ = file.Close()
+		return err
+	}
+	if err := file.Sync(); err != nil {
+		_ = file.Close()
+		return err
+	}
+	if err := file.Close(); err != nil {
+		return err
+	}
+	return os.Rename(file.Name(), libraryCachePath(outputDir))
+}
+
+func (a *UIApp) loadLibrary() {
+	cache, err := readLibraryCache(a.cfg.dataDirectory())
+	if err == nil {
+		a.downloader.restoreHongguoCatalog(cache.HongguoApp)
+	}
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	if err != nil {
+		if !errors.Is(err, os.ErrNotExist) {
+			a.libraryError = a.redactError(err)
+		}
+		return
+	}
+	if len(cache.Dramas) > 0 && (len(a.dramas) == 0 || !a.loadedAt.After(cache.LoadedAt)) {
+		a.dramas = cache.Dramas
+		a.normalizeDramaCovers(a.dramas)
+		a.loadedAt = cache.LoadedAt
+		a.libraryError = cache.LastError
+	}
+	a.librarySources = cache.Sources
+	if cache.HongguoApp != nil {
+		a.libraryApp = a.downloader.hongguoCatalogSnapshot()
+	}
+	for source, state := range a.librarySources {
+		if state.Status == "loading" {
+			state.Status = "partial"
+			state.Error = "上次更新中断，当前显示已保存数据，可手动刷新"
+			a.librarySources[source] = state
+		}
+	}
+	if sourceErrors := librarySourceErrors(a.librarySources); sourceErrors != "" {
+		a.libraryError = sourceErrors
+	}
+	a.libraryRevision = 1
+	if len(a.dramas) > 0 {
+		if _, err := os.Stat(libraryCachePath(a.cfg.dataDirectory())); errors.Is(err, os.ErrNotExist) {
+			if err := writeLibraryCache(a.cfg.dataDirectory(), libraryCache{Dramas: a.dramas, LoadedAt: a.loadedAt, LastError: a.libraryError, Sources: a.librarySources, HongguoApp: a.libraryApp}); err != nil {
+				a.libraryError = "剧库缓存保存失败: " + a.redactError(err)
+				return
+			}
+		}
+		a.librarySaved = true
+		var pending []Drama
+		for _, drama := range a.dramas {
+			if drama.SortMetadata != nil && drama.SortMetadata.Pending {
+				pending = append(pending, drama)
+			}
+		}
+		a.enqueueSortMetadataLocked(pending, false)
+		fmt.Printf("已恢复本地剧库：%d 部，缓存：%s\n", len(a.dramas), libraryCachePath(a.cfg.dataDirectory()))
+	}
+}
+
+func (d *Downloader) GetAllDramas(ctx context.Context) ([]Drama, error) {
+	cache, err := readLibraryCache(d.cfg.dataDirectory())
+	if err == nil {
+		d.restoreHongguoCatalog(cache.HongguoApp)
+	}
+	if err == nil && len(cache.Dramas) > 0 {
+		fmt.Printf("使用本地剧库缓存：%d 部（%s），更新请使用 -refresh\n", len(cache.Dramas), cache.LoadedAt.Format("2006-01-02 15:04:05"))
+		if cache.LastError != "" {
+			return cache.Dramas, errors.New(cache.LastError)
+		}
+		return cache.Dramas, nil
+	}
+	if err != nil && !errors.Is(err, os.ErrNotExist) {
+		fmt.Printf("  读取本地剧库缓存失败: %v\n", err)
+	}
+	return d.RefreshDramas(ctx, "")
+}
+
+func (d *Downloader) RefreshDramas(ctx context.Context, source string) ([]Drama, error) {
+	cached, _ := readLibraryCache(d.cfg.dataDirectory())
+	d.restoreHongguoCatalog(cached.HongguoApp)
+	ctx = withKnownHongguoDramas(ctx, cached.Dramas)
+	fresh, loadErr := d.fetchAllDramas(ctx, source)
+	merged := mergeSourceDramas(cached.Dramas, fresh, loadErr, source)
+	if len(fresh) == 0 && len(merged) == 0 {
+		return nil, loadErr
+	}
+	cache := libraryCache{Dramas: merged, LoadedAt: time.Now(), HongguoApp: d.hongguoCatalogSnapshot()}
+	if len(fresh) == 0 {
+		cache.LoadedAt = cached.LoadedAt
+	}
+	if loadErr != nil {
+		cache.LastError = publicError(loadErr).Error()
+	}
+	if err := writeLibraryCache(d.cfg.dataDirectory(), cache); err != nil {
+		loadErr = errors.Join(loadErr, fmt.Errorf("剧库缓存保存失败: %w", err))
+	}
+	fmt.Printf("本地剧库：%d 部，本次新增 %d 部\n", len(merged), len(merged)-len(cached.Dramas))
+	return merged, loadErr
+}
diff --git a/internal/app/library_cover_metadata_test.go b/internal/app/library_cover_metadata_test.go
new file mode 100644
index 0000000..a44a3e4
--- /dev/null
+++ b/internal/app/library_cover_metadata_test.go
@@ -0,0 +1,109 @@
+package app
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+const coverAddressFixture = "https://p3-reading-sign.fqnovelpic.com/synthetic-cover-address?fixture=1"
+
+func TestHongguoRankingKeepsCoverAddressForLibrary(t *testing.T) {
+	board, _ := findRankingBoard("hongguo-hot")
+	rows := rankingRows(1)
+	rows[0]["cover"] = coverAddressFixture
+	page, err := parseHongguoRanking(rankingFixture(board, 1, rows), board, 1)
+	if err != nil || bestDramaCover(page.Items[0].Drama) != coverAddressFixture || bestDramaCover(page.Items[1].Drama) != "" {
+		t.Fatal("ranking discarded its cover address or invented one", err)
+	}
+	d := rankingTestDownloader(t, func(request *http.Request) (*http.Response, error) {
+		t.Error("retaining an address must not fetch the image", request.URL.Path)
+		return rankingHTTPResponse(request, 404, ""), nil
+	})
+	app := &UIApp{downloader: d, cfg: d.cfg, metadataClosed: true}
+	page.BoardID, page.Page, page.FetchedAt = board.ID, 1, time.Now()
+	app.acceptRankingDramas(page)
+	for _, drama := range app.dramas {
+		if drama.ID == page.Items[0].Drama.ID && drama.Cover != "/api/ui/image?url="+url.QueryEscape(coverAddressFixture)+"&dramaId="+url.QueryEscape(drama.ID) {
+			t.Fatal("ranking address bypassed the local cover route")
+		}
+	}
+	for _, invalid := range []any{"javascript:invalid", "https://example.invalid/cover", "http://p3-reading-sign.fqnovelpic.com/cover", map[string]any{"unexpected": "field"}} {
+		rows[0]["cover"] = invalid
+		result, err := parseHongguoRanking(rankingFixture(board, 1, rows), board, 1)
+		if err != nil || len(result.Items) != 2 || bestDramaCover(result.Items[0].Drama) != "" {
+			t.Fatal("invalid optional address broke the ranking or reached the library", err)
+		}
+	}
+}
+
+func TestHistoricalMissingCoverWaitsForManualUpdate(t *testing.T) {
+	for _, found := range []bool{true, false} {
+		t.Run(fmt.Sprintf("address=%t", found), func(t *testing.T) {
+			var calls atomic.Int32
+			d := rankingTestDownloader(t, func(request *http.Request) (*http.Response, error) {
+				calls.Add(1)
+				if request.URL.Path != "/novel/player/video_detail/v1/" || request.Context().Value(backgroundCatalogKey{}) != true {
+					t.Error("cover metadata used a non-background or non-text request", request.URL.Path)
+					return rankingHTTPResponse(request, 404, ""), nil
+				}
+				cover := ""
+				if found {
+					cover = coverAddressFixture
+				}
+				return rankingHTTPResponse(request, 200, fmt.Sprintf(`{"data":{"video_data":{"series_id_str":"7000000000000000001","series_title":"合成资料","series_cover":%q,"hot_score":999,"series_play_cnt":999}}}`, cover)), nil
+			})
+			old := Drama{ID: "hongguo:7000000000000000001", Source: sourceHongguo, Title: "历史榜单条目", OnlineDate: "2026-09-01", Heat: "20019", Views: "0",
+				SortMetadata: &sortMetadataState{Version: sortMetadataVersion, CheckedAt: time.Now().Add(-time.Hour)}}
+			if err := writeLibraryCache(d.cfg.dataDirectory(), libraryCache{Dramas: []Drama{old}}); err != nil {
+				t.Fatal(err)
+			}
+			app := &UIApp{downloader: d, cfg: d.cfg}
+			t.Cleanup(app.stopSortMetadata)
+			app.loadLibrary()
+			app.handleDramas(httptest.NewRecorder(), httptest.NewRequest(http.MethodGet, "/api/ui/dramas", nil))
+			app.mu.Lock()
+			if calls.Load() != 0 || app.metadataDone != nil || len(app.newSortMetadataDramasLocked([]Drama{old})) != 0 || sortMetadataRemaining(app.dramas)[sourceHongguo] != 1 {
+				app.mu.Unlock()
+				t.Fatal("ordinary loading migrated historical addresses or hid their pending update")
+			}
+			app.enqueueHistoricalMetadataLocked(sourceHongguo, []string{old.ID})
+			app.mu.Unlock()
+			waitSortMetadataQueue(t, app)
+			cache, err := readLibraryCache(d.cfg.dataDirectory())
+			if err != nil || len(cache.Dramas) != 1 {
+				t.Fatal("manual address repair was not persisted", err)
+			}
+			updated := cache.Dramas[0]
+			if calls.Load() != 1 || updated.SortMetadata == nil || !updated.SortMetadata.CoverChecked || needsSortMetadata(updated) || updated.Views != "0" || updated.Heat != old.Heat || updated.Title != old.Title {
+				t.Fatal("cover repair changed primary metadata or did not remember a completed check")
+			}
+			if found && (bestDramaCover(updated) != coverAddressFixture || !strings.HasPrefix(updated.Cover.(string), "/api/ui/image?url=")) || !found && bestDramaCover(updated) != "" {
+				t.Fatal("manual repair lost the address or invented a missing cover")
+			}
+			app.mu.Lock()
+			app.enqueueHistoricalMetadataLocked(sourceHongguo, []string{old.ID})
+			app.mu.Unlock()
+			waitSortMetadataQueue(t, app)
+			if calls.Load() != 1 {
+				t.Fatal("known missing cover triggered repeated requests")
+			}
+		})
+	}
+}
+
+func TestHongguoCoverRepairValidatesDramaIdentity(t *testing.T) {
+	d := rankingTestDownloader(t, func(request *http.Request) (*http.Response, error) {
+		return rankingHTTPResponse(request, 200, fmt.Sprintf(`{"data":{"video_data":{"series_id_str":"7000000000000000002","series_cover":%q}}}`, coverAddressFixture)), nil
+	})
+	patch, err := d.fetchDramaSortMetadata(context.Background(), Drama{ID: "hongguo:7000000000000000001", OnlineDate: "2026-09-01", Heat: "1", Views: "0"})
+	if err == nil || bestDramaCover(patch) != "" {
+		t.Fatal("cover repair accepted another drama's address")
+	}
+}
diff --git a/internal/app/library_fetch.go b/internal/app/library_fetch.go
new file mode 100644
index 0000000..6197e20
--- /dev/null
+++ b/internal/app/library_fetch.go
@@ -0,0 +1,98 @@
+package app
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+)
+
+func (d *Downloader) fetchAllDramas(ctx context.Context, sourceFilter string) ([]Drama, error) {
+	if sourceFilter != "" && canonicalProviderSource(sourceFilter) != sourceHongguo {
+		return nil, errors.New("此版本仅支持红果站源")
+	}
+	if more, _ := ctx.Value(libraryMoreKey{}).(bool); more {
+		return d.fetchMoreLibrary(ctx, sourceFilter)
+	}
+	category, _ := ctx.Value(libraryCategoryKey{}).(string)
+	fmt.Println("正在获取红果剧库列表...")
+	ctx, cancel := context.WithTimeout(ctx, 10*time.Minute)
+	defer cancel()
+	dramas, err := d.fetchHongguoCategoryDramas(ctx, category)
+	dramas = onlyHongguoDramas(dramas)
+	if len(dramas) == 0 && err == nil && !hongguoCatalogInitialized(d.hongguoCatalogSnapshot()) {
+		err = errors.New("未返回可识别的视频数据")
+	}
+	reportLibraryProgress(ctx, sourceHongguo, dramas, err, true)
+	fmt.Printf(" 剧库获取完成：%d 部\n", len(dramas))
+	if err != nil {
+		fmt.Printf(" 红果获取失败: %v\n", publicError(err))
+		return dramas, &libraryLoadError{failures: map[string]error{sourceHongguo: err}}
+	}
+	return dramas, nil
+}
+
+func (d *Downloader) GetDramaChapters(ctx context.Context, seriesID string) (string, []Chapter, error) {
+	_, sourceID, valid := splitProviderDramaID(seriesID)
+	if !valid {
+		return "", nil, errors.New("仅支持红果剧集 ID，可填写 hongguo:数字ID 或数字ID")
+	}
+	title, chapters, err := d.fetchHongguoChapters(ctx, sourceID)
+	return title, uniqueChapters(chapters), err
+}
+
+func uniqueChapters(chapters []Chapter) []Chapter {
+	seen := map[string]bool{}
+	var out []Chapter
+	for i, ch := range chapters {
+		key := ch.ID
+		if key == "" {
+			key = ch.VideoURL
+		}
+		if key == "" {
+			key = fmt.Sprintf("idx_%d", i)
+		}
+		if seen[key] {
+			continue
+		}
+		seen[key] = true
+		out = append(out, ch)
+	}
+	return out
+}
+
+func (d *Downloader) BuildDramaTasks(ctx context.Context, drama Drama) ([]Task, error) {
+	return d.buildDramaTasksInDirectory(ctx, drama, "")
+}
+
+func (d *Downloader) buildDramaTasksInDirectory(ctx context.Context, drama Drama, existingDirectory string) ([]Task, error) {
+	var valid bool
+	drama, valid = normalizeHongguoDrama(drama)
+	if !valid {
+		return nil, errors.New("此版本仅支持红果剧集")
+	}
+	title, chapters, err := d.GetDramaChapters(ctx, drama.ID)
+	if err != nil {
+		return nil, err
+	}
+	if len(chapters) == 0 {
+		return nil, nil
+	}
+	drama = d.hongguoCachedDrama(drama)
+	dramaDir, err := d.downloadDramaDirectory(drama, title, existingDirectory)
+	if err != nil {
+		return nil, err
+	}
+	var tasks []Task
+	for i, ch := range chapters {
+		ep := ch.EpisodeString(i + 1)
+		epNum := padEpisode(ep)
+		fileName := safeFilename(epNum + ".mp4")
+		outPath, err := safeJoin(dramaDir, fileName)
+		if err != nil {
+			return nil, err
+		}
+		tasks = append(tasks, Task{DramaID: drama.ID, DramaTitle: title, Chapter: ch, Index: i + 1, Total: len(chapters), OutPath: outPath, ReleaseStatus: dramaReleaseStatus(drama)})
+	}
+	return tasks, nil
+}
diff --git a/internal/app/library_metadata.go b/internal/app/library_metadata.go
new file mode 100644
index 0000000..8f279df
--- /dev/null
+++ b/internal/app/library_metadata.go
@@ -0,0 +1,252 @@
+package app
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+)
+
+const sortMetadataVersion = 1
+const sortMetadataBatchSize = 40
+const sortMetadataRetryDelay = 5 * time.Minute
+const sortMetadataMissingRetryDelay = 24 * time.Hour
+
+type sortMetadataState struct {
+	Version      int       `json:"version"`
+	CheckedAt    time.Time `json:"checkedAt"`
+	Pending      bool      `json:"pending,omitempty"`
+	CoverChecked bool      `json:"coverChecked,omitempty"`
+	RetryAt      time.Time `json:"retryAt,omitempty"`
+	LastError    string    `json:"lastError,omitempty"`
+}
+
+type libraryRowsKey struct{}
+type libraryPriorityKey struct{}
+type libraryMetadataProgressKey struct{}
+
+type libraryMetadataProgress struct {
+	Running bool `json:"running"`
+	Checked int  `json:"checked"`
+	Total   int  `json:"total"`
+	Updated int  `json:"updated"`
+	Failed  int  `json:"failed"`
+}
+
+func supportsSortMetadata(drama Drama) bool {
+	switch dramaProvider(drama) {
+	case sourceHongguo:
+		return true
+	}
+	return false
+}
+
+func needsSortMetadata(drama Drama) bool {
+	return supportsSortMetadata(drama) && (drama.SortMetadata == nil || drama.SortMetadata.Version != sortMetadataVersion || needsHongguoCoverAddress(drama))
+}
+
+func sortMetadataRetryAt(state *sortMetadataState, now time.Time) time.Time {
+	if state == nil || state.Version != 0 {
+		return time.Time{}
+	}
+	if !state.RetryAt.IsZero() {
+		return state.RetryAt
+	}
+	if state.CheckedAt.IsZero() {
+		return time.Time{}
+	}
+	return state.CheckedAt.Add(sortMetadataRetryDelay)
+}
+
+func sortMetadataFailureDelay(err error) time.Duration {
+	var status *httpStatusError
+	if errors.As(err, &status) && (status.status == http.StatusNotFound || status.status == http.StatusGone) {
+		return sortMetadataMissingRetryDelay
+	}
+	text := strings.ToLower(err.Error())
+	if strings.Contains(text, "无效的") || strings.Contains(text, "未返回所请求") || strings.Contains(text, "返回了其他剧集") || strings.Contains(text, "与请求剧集不符") {
+		return sortMetadataMissingRetryDelay
+	}
+	return sortMetadataRetryDelay
+}
+
+func failedSortMetadataState(drama Drama, err error, now time.Time) *sortMetadataState {
+	state := &sortMetadataState{CheckedAt: now, RetryAt: now.Add(sortMetadataFailureDelay(err)), LastError: truncate(publicError(err).Error(), 300)}
+	if drama.SortMetadata != nil {
+		state.CoverChecked = drama.SortMetadata.CoverChecked
+	}
+	return state
+}
+
+func needsHongguoCoverAddress(drama Drama) bool {
+	return dramaProvider(drama) == sourceHongguo && bestDramaCover(drama) == "" &&
+		(drama.SortMetadata == nil || !drama.SortMetadata.CoverChecked)
+}
+
+func selectSortMetadataBatch(dramas []Drama, source string, priority []string, now time.Time) []Drama {
+	positions := make(map[string]int, len(priority))
+	for index, id := range priority {
+		if _, found := positions[id]; !found {
+			positions[id] = index
+		}
+	}
+	var candidates []Drama
+	seen := map[string]bool{}
+	for _, drama := range dramas {
+		if seen[drama.ID] || !matchesSourceFilter(dramaProvider(drama), source) || !needsSortMetadata(drama) {
+			continue
+		}
+		seen[drama.ID] = true
+		if retryAt := sortMetadataRetryAt(drama.SortMetadata, now); !retryAt.IsZero() && now.Before(retryAt) {
+			continue
+		}
+		candidates = append(candidates, drama)
+	}
+	sort.SliceStable(candidates, func(i, j int) bool {
+		left, leftOK := positions[candidates[i].ID]
+		right, rightOK := positions[candidates[j].ID]
+		if leftOK != rightOK {
+			return leftOK
+		}
+		if leftOK && left != right {
+			return left < right
+		}
+		var leftTime, rightTime time.Time
+		if candidates[i].SortMetadata != nil {
+			leftTime = candidates[i].SortMetadata.CheckedAt
+		}
+		if candidates[j].SortMetadata != nil {
+			rightTime = candidates[j].SortMetadata.CheckedAt
+		}
+		return leftTime.Before(rightTime)
+	})
+	if len(candidates) > sortMetadataBatchSize {
+		candidates = candidates[:sortMetadataBatchSize]
+	}
+	return candidates
+}
+
+func sortMetadataRemaining(dramas []Drama) map[string]int {
+	counts := map[string]int{"": 0, "hongguo": 0}
+	for _, drama := range dramas {
+		if !needsSortMetadata(drama) {
+			continue
+		}
+		source := dramaProvider(drama)
+		counts[source]++
+		counts[""]++
+	}
+	return counts
+}
+
+func reportMetadataProgress(ctx context.Context, progress libraryMetadataProgress) {
+	if callback, ok := ctx.Value(libraryMetadataProgressKey{}).(func(libraryMetadataProgress)); ok {
+		callback(progress)
+	}
+}
+
+func (d *Downloader) backfillSortMetadata(ctx context.Context, source string) ([]Drama, map[string]error) {
+	rows, _ := ctx.Value(libraryRowsKey{}).([]Drama)
+	priority, _ := ctx.Value(libraryPriorityKey{}).([]string)
+	batch := selectSortMetadataBatch(rows, source, priority, time.Now())
+	progress := libraryMetadataProgress{Running: true, Total: len(batch)}
+	reportMetadataProgress(ctx, progress)
+	defer func() { progress.Running = false; reportMetadataProgress(ctx, progress) }()
+	failures := map[string]error{}
+	if len(batch) == 0 {
+		return nil, failures
+	}
+	workCtx, cancel := context.WithTimeout(ctx, 3*time.Minute)
+	defer cancel()
+	type result struct {
+		patch    Drama
+		previous Drama
+		err      error
+	}
+	jobs := make(chan Drama, len(batch))
+	results := make(chan result, len(batch))
+	for _, drama := range batch {
+		jobs <- drama
+	}
+	close(jobs)
+	workers := d.cfg.RequestConcurrency
+	if workers < 1 {
+		workers = 1
+	}
+	if workers > 3 {
+		workers = 3
+	}
+	var group sync.WaitGroup
+	for worker := 0; worker < workers; worker++ {
+		group.Add(1)
+		go func() {
+			defer group.Done()
+			for drama := range jobs {
+				if workCtx.Err() != nil {
+					return
+				}
+				itemCtx, stop := context.WithTimeout(workCtx, 40*time.Second)
+				patch, err := d.fetchDramaSortMetadata(itemCtx, drama)
+				stop()
+				now := time.Now()
+				patch.SortMetadata = &sortMetadataState{CheckedAt: now}
+				if err == nil {
+					patch.SortMetadata.Version = sortMetadataVersion
+					patch.SortMetadata.CoverChecked = true
+				} else {
+					patch.SortMetadata = failedSortMetadataState(drama, err, now)
+				}
+				results <- result{patch: patch, previous: drama, err: err}
+			}
+		}()
+	}
+	go func() { group.Wait(); close(results) }()
+	var patches []Drama
+	for result := range results {
+		patch := result.patch
+		provider := dramaProvider(result.previous)
+		if result.err != nil {
+			progress.Failed++
+			if failures[provider] == nil {
+				failures[provider] = fmt.Errorf("部分历史资料未补齐，可稍后重试: %w", result.err)
+			}
+		}
+		if patch.OnlineDate != "" && patch.OnlineDate != result.previous.OnlineDate || patch.Heat != "" && patch.Heat != result.previous.Heat || patch.Views != "" && patch.Views != result.previous.Views || bestDramaCover(patch) != "" && bestDramaCover(patch) != bestDramaCover(result.previous) {
+			progress.Updated++
+		}
+		patches = append(patches, patch)
+		progress.Checked++
+		reportLibraryProgress(ctx, provider, []Drama{patch}, nil, false)
+		reportMetadataProgress(ctx, progress)
+	}
+	if progress.Checked < len(batch) {
+		for _, drama := range batch {
+			provider := dramaProvider(drama)
+			if failures[provider] == nil {
+				failures[provider] = errors.New("本批补齐已暂停，剩余条目可再次手动补齐")
+			}
+		}
+	}
+	return patches, failures
+}
+
+func (d *Downloader) fetchMoreLibrary(ctx context.Context, source string) ([]Drama, error) {
+	category, _ := ctx.Value(libraryCategoryKey{}).(string)
+	patches, failures := d.backfillSortMetadata(ctx, source)
+	if matchesSourceFilter(sourceHongguo, source) {
+		items, err := d.fetchHongguoCategoryDramas(ctx, category)
+		if err != nil {
+			failures[sourceHongguo] = errors.Join(failures[sourceHongguo], err)
+		}
+		reportLibraryProgress(ctx, sourceHongguo, items, failures[sourceHongguo], true)
+		patches = mergeSourceDramas(patches, items, nil, sourceHongguo)
+	}
+	if len(failures) > 0 {
+		return patches, &libraryLoadError{failures: failures}
+	}
+	return patches, nil
+}
diff --git a/internal/app/library_metadata_queue.go b/internal/app/library_metadata_queue.go
new file mode 100644
index 0000000..52b54e8
--- /dev/null
+++ b/internal/app/library_metadata_queue.go
@@ -0,0 +1,185 @@
+package app
+
+import (
+	"context"
+	"time"
+)
+
+func (a *UIApp) newSortMetadataDramasLocked(items []Drama) []Drama {
+	known := make(map[string]bool, len(a.dramas))
+	for _, drama := range a.dramas {
+		known[drama.ID] = true
+	}
+	var fresh []Drama
+	for _, drama := range items {
+		if drama.ID != "" && !known[drama.ID] {
+			known[drama.ID] = true
+			if needsSortMetadata(drama) {
+				fresh = append(fresh, drama)
+			}
+		}
+	}
+	return fresh
+}
+
+func (a *UIApp) enqueueHistoricalMetadataLocked(source string, priority []string) {
+	var available []Drama
+	for _, drama := range a.dramas {
+		if !a.metadataPending[drama.ID] {
+			available = append(available, drama)
+		}
+	}
+	a.enqueueSortMetadataLocked(selectSortMetadataBatch(available, source, priority, time.Now()), true)
+}
+
+func (a *UIApp) enqueueSortMetadataLocked(items []Drama, prioritize bool) {
+	if a.metadataClosed || len(items) == 0 {
+		return
+	}
+	if a.metadataPending == nil {
+		a.metadataPending = map[string]bool{}
+	}
+	var added []string
+	for _, drama := range items {
+		if drama.ID == "" || !needsSortMetadata(drama) || a.metadataPending[drama.ID] {
+			continue
+		}
+		a.metadataPending[drama.ID] = true
+		added = append(added, drama.ID)
+	}
+	if len(added) == 0 {
+		return
+	}
+
+	for index, drama := range a.dramas {
+		if !a.metadataPending[drama.ID] || drama.SortMetadata != nil && drama.SortMetadata.Pending {
+			continue
+		}
+		state := sortMetadataState{Pending: true}
+		if drama.SortMetadata != nil {
+			state = *drama.SortMetadata
+			state.Pending = true
+		}
+		a.dramas[index].SortMetadata = &state
+	}
+	if prioritize {
+		a.metadataQueue = append(added, a.metadataQueue...)
+	} else {
+		a.metadataQueue = append(a.metadataQueue, added...)
+	}
+	if !a.libraryMetadata.Running {
+		a.libraryMetadata = libraryMetadataProgress{Running: true}
+	}
+	a.libraryMetadata.Total += len(added)
+	a.libraryDirty = true
+	a.libraryRevision++
+	if a.metadataDone == nil {
+		ctx, cancel := context.WithCancel(context.Background())
+		a.metadataCancel = cancel
+		a.metadataDone = make(chan struct{})
+		go a.runSortMetadataQueue(ctx, a.metadataDone)
+	}
+}
+
+func (a *UIApp) runSortMetadataQueue(ctx context.Context, done chan struct{}) {
+
+	ctx = context.WithValue(ctx, backgroundCatalogKey{}, true)
+	for {
+		a.mu.Lock()
+		if ctx.Err() != nil || len(a.metadataQueue) == 0 {
+			a.mu.Unlock()
+			a.persistLibrary()
+			a.mu.Lock()
+
+			if ctx.Err() == nil && len(a.metadataQueue) > 0 {
+				a.mu.Unlock()
+				continue
+			}
+			a.libraryMetadata.Running = false
+			a.libraryRevision++
+			a.metadataCancel()
+			a.metadataCancel = nil
+			a.metadataDone = nil
+			a.metadataQueue = nil
+			close(done)
+			a.mu.Unlock()
+			return
+		}
+		if a.libraryLoading != nil {
+			a.mu.Unlock()
+			timer := time.NewTimer(500 * time.Millisecond)
+			select {
+			case <-ctx.Done():
+			case <-timer.C:
+			}
+			timer.Stop()
+			continue
+		}
+		id := a.metadataQueue[0]
+		a.metadataQueue = a.metadataQueue[1:]
+		var previous Drama
+		for _, drama := range a.dramas {
+			if drama.ID == id {
+				previous = drama
+				break
+			}
+		}
+		a.mu.Unlock()
+		itemCtx, cancel := context.WithTimeout(ctx, 40*time.Second)
+		patch, err := a.downloader.fetchDramaSortMetadata(itemCtx, previous)
+		cancel()
+		if err != nil && ctx.Err() == nil {
+			a.downloader.recordDiagnostic(diagnosticEvent{Event: "metadata.failed", Source: dramaProvider(previous), DramaID: previous.ID, DramaTitle: previous.DisplayTitle(), Message: err.Error()})
+		}
+		patch.SortMetadata = &sortMetadataState{CheckedAt: time.Now()}
+		if err == nil {
+			patch.SortMetadata.Version = sortMetadataVersion
+			patch.SortMetadata.CoverChecked = true
+		}
+		normalizeDramaCover(&patch)
+		a.mu.Lock()
+		if ctx.Err() != nil {
+
+			a.mu.Unlock()
+			continue
+		}
+		delete(a.metadataPending, id)
+		for index, drama := range a.dramas {
+			if drama.ID != id {
+				continue
+			}
+			if patch.OnlineDate != "" && patch.OnlineDate != drama.OnlineDate || patch.Heat != "" && patch.Heat != drama.Heat || patch.Views != "" && patch.Views != drama.Views || bestDramaCover(patch) != "" && bestDramaCover(patch) != bestDramaCover(drama) {
+				a.libraryMetadata.Updated++
+			}
+
+			patch.Title, patch.Name = drama.Title, drama.Name
+			a.dramas[index] = mergeDramaMetadata(patch, drama)
+			break
+		}
+		a.libraryMetadata.Checked++
+		if err != nil {
+			a.libraryMetadata.Failed++
+		}
+		a.libraryDirty = true
+		a.libraryRevision++
+		persist := time.Since(a.libraryLastSave) >= 3*time.Second
+		if persist {
+			a.libraryLastSave = time.Now()
+		}
+		a.mu.Unlock()
+		if persist {
+			a.persistLibrary()
+		}
+	}
+}
+
+func (a *UIApp) stopSortMetadata() {
+	a.mu.Lock()
+	a.metadataClosed = true
+	cancel, done := a.metadataCancel, a.metadataDone
+	a.mu.Unlock()
+	if cancel != nil {
+		cancel()
+		<-done
+	}
+}
diff --git a/internal/app/library_metadata_queue_test.go b/internal/app/library_metadata_queue_test.go
new file mode 100644
index 0000000..a787aa9
--- /dev/null
+++ b/internal/app/library_metadata_queue_test.go
@@ -0,0 +1,243 @@
+package app
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func waitSortMetadataQueue(t *testing.T, app *UIApp) {
+	t.Helper()
+	app.mu.Lock()
+	done := app.metadataDone
+	app.mu.Unlock()
+	if done != nil {
+		select {
+		case <-done:
+		case <-time.After(5 * time.Second):
+			t.Fatal("metadata queue did not finish")
+		}
+	}
+}
+
+func TestPrimaryCatalogReturnsBeforeOptionalMetadata(t *testing.T) {
+	for _, source := range []string{sourceHongguo} {
+		t.Run(source, func(t *testing.T) {
+			id := "7615465407347952664"
+			started, release := make(chan struct{}), make(chan struct{})
+			var once sync.Once
+			var calls atomic.Int32
+			d := rankingTestDownloader(t, func(request *http.Request) (*http.Response, error) {
+				calls.Add(1)
+				if request.Context().Value(backgroundCatalogKey{}) != true {
+					t.Error("optional detail did not use background priority")
+				}
+				once.Do(func() { close(started) })
+				select {
+				case <-release:
+				case <-request.Context().Done():
+					return nil, request.Context().Err()
+				}
+				switch request.URL.Path {
+				case "/detail":
+					if request.URL.Query().Get("series_id") != id {
+						t.Error("historical entry was automatically fetched")
+					}
+					return rankingHTTPResponse(request, 200, sortDetailFixture(id, "1773662280")), nil
+				case "/novel/player/video_detail/v1/":
+					return rankingHTTPResponse(request, 200, fmt.Sprintf(`{"data":{"video_data":{"series_id_str":%q,"series_title":"详情标题","hot_score":20019,"series_play_cnt":10019}}}`, id)), nil
+				default:
+					t.Errorf("unexpected metadata request: %s", request.URL.Path)
+					return rankingHTTPResponse(request, 404, ""), nil
+				}
+			})
+			old := Drama{ID: providerDramaID(source, "7498612570866076734"), Source: source, Title: "历史条目"}
+			fresh := Drama{ID: providerDramaID(source, id), Source: source, Title: "列表标题", Heat: "20019", Views: "0", Cover: coverAddressFixture}
+			app := &UIApp{downloader: d, cfg: d.cfg, dramas: []Drama{old}, librarySources: map[string]librarySourceState{}, libraryLoading: make(chan struct{})}
+			t.Cleanup(app.stopSortMetadata)
+			app.acceptLibraryProgress(source, []Drama{old, fresh}, nil, false)
+			app.mu.Lock()
+			if calls.Load() != 0 || len(app.dramas) != 2 || app.dramas[1].Heat != fresh.Heat || app.dramas[1].Views != "0" {
+				t.Error("primary fields did not return before optional requests")
+			}
+			close(app.libraryLoading)
+			app.libraryLoading = nil
+			app.mu.Unlock()
+			select {
+			case <-started:
+			case <-time.After(2 * time.Second):
+				t.Fatal("new entry was not scheduled automatically")
+			}
+
+			app.acceptLibraryProgress(source, []Drama{fresh, old}, nil, true)
+			writer := httptest.NewRecorder()
+			app.handleDramas(writer, httptest.NewRequest("GET", "/api/ui/dramas", nil))
+			var snapshot struct {
+				Loading  bool                    `json:"loading"`
+				Metadata libraryMetadataProgress `json:"metadata"`
+			}
+			if json.Unmarshal(writer.Body.Bytes(), &snapshot) != nil || snapshot.Loading || !snapshot.Metadata.Running || snapshot.Metadata.Total != 1 {
+				t.Fatal("optional metadata blocked the library or duplicated work")
+			}
+			close(release)
+			waitSortMetadataQueue(t, app)
+			cache, err := readLibraryCache(d.cfg.dataDirectory())
+			if err != nil {
+				t.Fatal(err)
+			}
+			for _, row := range cache.Dramas {
+				if row.ID == old.ID && row.SortMetadata != nil {
+					t.Error("ordinary catalog refresh enrolled historical data")
+				}
+				wantViews := "10019次播放"
+				if source == sourceHongguo {
+					wantViews = "0"
+				}
+				if row.ID == fresh.ID && (row.OnlineDate != "2026-03-16" || row.Views != wantViews || row.Heat != fresh.Heat || row.Title != "列表标题" || row.SortMetadata == nil || row.SortMetadata.Version != sortMetadataVersion || row.SortMetadata.Pending) {
+					t.Errorf("asynchronous metadata was not merged correctly: %+v", row)
+				}
+			}
+			if calls.Load() != 1 {
+				t.Fatalf("duplicate detail requests: %d", calls.Load())
+			}
+		})
+	}
+}
+
+func TestResumeOnlyPreviouslyQueuedMetadata(t *testing.T) {
+	var calls atomic.Int32
+	d := rankingTestDownloader(t, func(request *http.Request) (*http.Response, error) {
+		calls.Add(1)
+		if request.URL.Path != "/detail" || request.URL.Query().Get("series_id") != "7000000000000000002" {
+			t.Errorf("unexpected resource: %s", request.URL.Path)
+		}
+		return rankingHTTPResponse(request, 200, sortDetailFixture("7000000000000000002", "0")), nil
+	})
+	cache := libraryCache{Dramas: []Drama{
+		{ID: "hongguo:7000000000000000001", Source: sourceHongguo, Title: "历史条目"},
+		{ID: "hongguo:7000000000000000002", Source: sourceHongguo, Title: "新条目", Heat: "0", Views: "0", Cover: coverAddressFixture, SortMetadata: &sortMetadataState{Pending: true}},
+	}}
+	if err := writeLibraryCache(d.cfg.dataDirectory(), cache); err != nil {
+		t.Fatal(err)
+	}
+	app := &UIApp{downloader: d, cfg: d.cfg}
+	t.Cleanup(app.stopSortMetadata)
+	app.loadLibrary()
+	waitSortMetadataQueue(t, app)
+	if calls.Load() != 1 {
+		t.Fatalf("resume requested %d resources, want one pending detail", calls.Load())
+	}
+	app.mu.Lock()
+	defer app.mu.Unlock()
+	if app.dramas[0].SortMetadata != nil || app.dramas[1].OnlineDate != "" || app.dramas[1].Views != "0" || app.dramas[1].SortMetadata.Version != sortMetadataVersion {
+		t.Fatal("resume changed history, lost zero, or invented an empty source date")
+	}
+}
+
+func TestPrimarySortFieldsNeedNoAdditionalInterfacesWhenComplete(t *testing.T) {
+	hongguo := hongguoDramaFromAny(map[string]any{"series_id": "7615465407347952664", "series_title": "列表剧", "series_cover": coverAddressFixture, "first_visible_time": "1773662280", "hot_score": "20019", "series_play_cnt": "0"}, "测试")
+	d := rankingTestDownloader(t, func(request *http.Request) (*http.Response, error) {
+		t.Errorf("complete primary data triggered an optional request: %s", request.URL.Path)
+		return rankingHTTPResponse(request, 404, ""), nil
+	})
+	for _, drama := range []Drama{hongguo} {
+		if drama.OnlineDate != "2026-03-16" || drama.Views != "0" || !hasCompleteSortMetadata(drama) {
+			t.Errorf("primary sort fields were lost: %+v", drama)
+		}
+		if _, err := d.fetchDramaSortMetadata(context.Background(), drama); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if hasSortMetric("未知") || hasSortMetric("-1") {
+		t.Fatal("unknown metrics were misclassified as available sorting data")
+	}
+}
+
+func TestBackgroundRequestsYieldToForeground(t *testing.T) {
+	limiter := newRequestLimiter(1, time.Nanosecond)
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+	request := httptest.NewRequest("GET", "https://hongguoduanju.com/search/test", nil)
+	release, err := limiter.acquire(ctx, request)
+	if err != nil {
+		t.Fatal(err)
+	}
+	background := make(chan func(), 1)
+	foreground := make(chan func(), 1)
+	go func() {
+		unlock, _ := limiter.acquire(context.WithValue(ctx, backgroundCatalogKey{}, true), request)
+		background <- unlock
+	}()
+	go func() {
+		unlock, _ := limiter.acquire(ctx, request)
+		foreground <- unlock
+	}()
+
+	for {
+		limiter.mu.Lock()
+		waiting := limiter.foregroundWaiting
+		limiter.mu.Unlock()
+		if waiting > 0 {
+			break
+		}
+		if ctx.Err() != nil {
+			t.Fatal("foreground waiter did not register")
+		}
+		time.Sleep(time.Millisecond)
+	}
+	release()
+	select {
+	case unlock := <-foreground:
+		if unlock == nil {
+			t.Fatal("foreground timed out")
+		}
+		select {
+		case <-background:
+			t.Fatal("background ran alongside a waiting foreground request")
+		default:
+		}
+		unlock()
+	case <-background:
+		t.Fatal("optional metadata overtook foreground work")
+	case <-ctx.Done():
+		t.Fatal(ctx.Err())
+	}
+	select {
+	case unlock := <-background:
+		if unlock == nil {
+			t.Fatal("background did not resume")
+		}
+		unlock()
+	case <-ctx.Done():
+		t.Fatal(ctx.Err())
+	}
+}
+
+func TestOptionalDetailPermissionFailureDoesNotBlockForeground(t *testing.T) {
+	limiter := newRequestLimiter(1, time.Nanosecond)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	foreground := httptest.NewRequest("GET", "https://hongguoduanju.com/search/test", nil).WithContext(ctx)
+	background := foreground.WithContext(context.WithValue(ctx, backgroundCatalogKey{}, true))
+	limiter.observe(background, &http.Response{StatusCode: http.StatusForbidden, Header: http.Header{}})
+	if release, err := limiter.acquire(background.Context(), background); err == nil {
+		release()
+		t.Fatal("repeated forbidden details must cool down")
+	}
+	release, err := limiter.acquire(ctx, foreground)
+	if err != nil {
+		t.Fatal("an optional detail's permissions blocked public search", err)
+	}
+	release()
+	limiter.observe(background, &http.Response{StatusCode: http.StatusTooManyRequests, Header: http.Header{"Retry-After": {"60"}}})
+	if release, err := limiter.acquire(ctx, foreground); err == nil {
+		release()
+		t.Fatal("site rate limits must still be respected")
+	}
+}
diff --git a/internal/app/library_metadata_test.go b/internal/app/library_metadata_test.go
new file mode 100644
index 0000000..73ddf71
--- /dev/null
+++ b/internal/app/library_metadata_test.go
@@ -0,0 +1,185 @@
+package app
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func sortDetailFixture(id, stamp string) string {
+	return `<script>window._ROUTER_DATA={"loaderData":{"detail_page":{"seriesDetail":{"series_id":"` + id + `","series_name":"测试剧","first_visible_time":"` + stamp + `","create_time":"1745906791"}}}}</script>`
+}
+
+func TestSortDetailDatesAndIdentity(t *testing.T) {
+	id := "7615465407347952664"
+	drama, err := parseHongguoSortDetail(sortDetailFixture(id, "1773662280"), id)
+	if err != nil || drama.OnlineDate != "2026-03-16" {
+		t.Fatalf("first-visible date: %q, %v", drama.OnlineDate, err)
+	}
+	if _, err = parseHongguoSortDetail(sortDetailFixture("7498612570866076734", "1773662280"), id); err == nil {
+		t.Fatal("accepted another drama's time")
+	}
+	drama, err = parseHongguoSortDetail(sortDetailFixture(id, "0"), id)
+	if err != nil || drama.OnlineDate != "" {
+		t.Fatal("creation time must not replace missing first-visible time")
+	}
+	for _, value := range []string{"", "0", "0001-01-01", "1970-01-01", "2101-01-01", "2026-02-31", "not a date"} {
+		if got := providerReleaseDate(value); got != "" {
+			t.Errorf("accepted date %q", value)
+		}
+	}
+	if normalizeViews("10019") != "10019次播放" {
+		t.Fatal("play counts must retain precision")
+	}
+}
+
+func TestSortMetadataSelectionAndResume(t *testing.T) {
+	now := time.Now()
+	var rows []Drama
+	for index := 0; index < 60; index++ {
+		rows = append(rows, Drama{ID: fmt.Sprintf("hongguo:%019d", index+1), Source: sourceHongguo})
+	}
+	rows[1].SortMetadata = &sortMetadataState{Version: sortMetadataVersion, CheckedAt: now, CoverChecked: true}
+	rows[2].SortMetadata = &sortMetadataState{CheckedAt: now}
+	rows = append(rows, Drama{ID: "huangdou:other", Source: "huangdou"})
+	batch := selectSortMetadataBatch(rows, sourceHongguo, []string{rows[59].ID, rows[59].ID, rows[2].ID, "huangdou:other"}, now)
+	if len(batch) != sortMetadataBatchSize || batch[0].ID != rows[59].ID {
+		t.Fatal("did not prioritize filtered entries within the batch limit")
+	}
+	for _, row := range batch {
+		if row.ID == rows[1].ID || row.ID == rows[2].ID || row.Source != sourceHongguo {
+			t.Fatal("selected completed, cooling-down or other-source entries")
+		}
+	}
+	if got := selectSortMetadataBatch(rows, "huangdou", nil, now); len(got) != 0 {
+		t.Fatal("source filter was not respected")
+	}
+	if remaining := sortMetadataRemaining(rows); remaining["hongguo"] != 59 || remaining["huangdou"] != 0 || remaining[""] != 59 {
+		t.Fatal(remaining)
+	}
+}
+
+func TestManualBackfillPersistsPartialResultsAndContinuesAfterCatalogEnd(t *testing.T) {
+	first, bad, unknown := "7615465407347952664", "7498612570866076734", "7677914379060251673"
+	var calls atomic.Int32
+	var fail atomic.Bool
+	fail.Store(true)
+	d := rankingTestDownloader(t, func(request *http.Request) (*http.Response, error) {
+		calls.Add(1)
+		switch request.URL.Path {
+		case "/detail":
+			id := request.URL.Query().Get("series_id")
+			stamp := "1773662280"
+			if id == unknown {
+				stamp = "0"
+			}
+			return rankingHTTPResponse(request, 200, sortDetailFixture(id, stamp)), nil
+		case "/novel/player/video_detail/v1/":
+			var body struct {
+				ID string `json:"series_id"`
+			}
+			json.NewDecoder(request.Body).Decode(&body)
+			if body.ID == bad && fail.Load() {
+				return rankingHTTPResponse(request, 503, "temporary failure"), nil
+			}
+			return rankingHTTPResponse(request, 200, fmt.Sprintf(`{"data":{"video_data":{"series_id_str":%q,"series_title":"测试剧","hot_score":20019,"series_play_cnt":10019}}}`, body.ID)), nil
+		default:
+			t.Errorf("backfill requested a non-detail resource: %s", request.URL.Path)
+			return rankingHTTPResponse(request, 404, ""), nil
+		}
+	})
+	client := d.hongguoClient()
+	client.mu.Lock()
+	for _, genre := range hongguoAppGenres {
+		client.state.Feeds[genre.key] = hongguoCatalogCursor{Initialized: true, Exhausted: true}
+	}
+	client.mu.Unlock()
+	a := &UIApp{downloader: d, cfg: d.cfg, libraryAttempted: true, librarySources: map[string]librarySourceState{}, libraryApp: d.hongguoCatalogSnapshot(), dramas: []Drama{
+		{ID: "hongguo:" + first, Source: sourceHongguo, Title: "原有标题", Views: "0"},
+		{ID: "hongguo:" + bad, Source: sourceHongguo, Title: "暂时失败", Heat: "800"},
+		{ID: "hongguo:" + unknown, Source: sourceHongguo, Title: "站点日期未知"},
+	}}
+	t.Cleanup(a.stopSortMetadata)
+	plain := httptest.NewRecorder()
+	a.handleDramas(plain, httptest.NewRequest("GET", "/api/ui/dramas", nil))
+	if calls.Load() != 0 {
+		t.Fatal("ordinary library reads must not backfill")
+	}
+	before := a.librarySnapshotLocked(0)
+	if before["hasMoreBySource"].(map[string]bool)[sourceHongguo] != true {
+		t.Fatal("backfill must remain available after the catalog is exhausted")
+	}
+	writer := httptest.NewRecorder()
+	a.handleDramas(writer, httptest.NewRequest("GET", "/api/ui/dramas?more=1&source=hongguo&priority=hongguo:"+first, nil))
+	if writer.Code != 200 {
+		t.Fatal(writer.Body.String())
+	}
+	waitSortMetadataQueue(t, a)
+	a.mu.Lock()
+	rows := append([]Drama(nil), a.dramas...)
+	progress := a.libraryMetadata
+	a.mu.Unlock()
+	if progress.Checked != 3 || progress.Failed != 1 {
+		t.Fatalf("unexpected progress: %+v", progress)
+	}
+	for _, row := range rows {
+		switch row.ID {
+		case "hongguo:" + first:
+			if row.OnlineDate != "2026-03-16" || row.Heat != "20019" || row.Views != "10019次播放" || row.SortMetadata.Version != sortMetadataVersion {
+				t.Fatal("fresh sorting fields were not merged")
+			}
+		case "hongguo:" + bad:
+			if row.OnlineDate == "" || row.Heat != "800" || row.SortMetadata.Version != 0 {
+				t.Fatal("partial success must survive a failed metrics request")
+			}
+		case "hongguo:" + unknown:
+			if row.OnlineDate != "" || row.SortMetadata.Version != sortMetadataVersion {
+				t.Fatal("a valid response with no date must not be retried forever or invent a date")
+			}
+		}
+	}
+	saved, err := readLibraryCache(d.cfg.dataDirectory())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if batch := selectSortMetadataBatch(saved.Dramas, sourceHongguo, nil, time.Now()); len(batch) != 0 {
+		t.Fatal("restart lost completed checks or failure cooldown")
+	}
+	for index, row := range saved.Dramas {
+		if row.ID == "hongguo:"+bad {
+			saved.Dramas[index].SortMetadata = &sortMetadataState{CheckedAt: time.Now().Add(-sortMetadataRetryDelay - time.Second)}
+		}
+	}
+	fail.Store(false)
+	previous := calls.Load()
+	patches, failures := d.backfillSortMetadata(withKnownHongguoDramas(context.Background(), saved.Dramas), sourceHongguo)
+	if len(failures) != 0 || len(patches) != 1 || patches[0].ID != "hongguo:"+bad || calls.Load()-previous != 1 {
+		t.Fatal("retry did not resume only the failed entry")
+	}
+}
+
+func TestManualMetadataPriorityValidation(t *testing.T) {
+	a := &UIApp{}
+	for _, path := range []string{
+		"/api/ui/dramas?more=1&source=invalid",
+		"/api/ui/dramas?more=1&refresh=1",
+		"/api/ui/dramas?update=1&refresh=1",
+		"/api/ui/dramas?update=1&more=1",
+		"/api/ui/dramas?update=1&source=invalid",
+		"/api/ui/dramas?update=1&priority=" + strings.Repeat("hongguo:700001,", sortMetadataBatchSize),
+		"/api/ui/dramas?update=1&priority=hongguo:" + strings.Repeat("1", 121),
+		"/api/ui/dramas?more=1&priority=" + strings.Repeat("id,", sortMetadataBatchSize),
+	} {
+		writer := httptest.NewRecorder()
+		a.handleDramas(writer, httptest.NewRequest("GET", path, nil))
+		if writer.Code != 400 {
+			t.Fatalf("invalid request was not rejected: %d", writer.Code)
+		}
+	}
+}
diff --git a/internal/app/library_progress.go b/internal/app/library_progress.go
new file mode 100644
index 0000000..fec7e9e
--- /dev/null
+++ b/internal/app/library_progress.go
@@ -0,0 +1,371 @@
+package app
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"sort"
+	"strings"
+	"time"
+)
+
+type librarySourceState struct {
+	Status    string    `json:"status"`
+	Count     int       `json:"count"`
+	Error     string    `json:"error,omitempty"`
+	Phase     string    `json:"phase,omitempty"`
+	UpdatedAt time.Time `json:"updatedAt"`
+}
+
+func (state librarySourceState) withPhase(phase string) librarySourceState {
+	phase = strings.TrimSpace(phase)
+	if state.Status == "loading" {
+		state.Phase = phase
+	}
+	return state
+}
+
+type libraryProgressKey struct{}
+type libraryCategoryKey struct{}
+type libraryProgressFunc func(string, []Drama, error, bool) error
+
+type libraryLoadMode int
+
+const (
+	libraryLoadRefresh libraryLoadMode = iota
+	libraryLoadMore
+	libraryLoadUpdate
+)
+
+func reportLibraryProgress(ctx context.Context, source string, items []Drama, err error, done bool) error {
+	if callback, ok := ctx.Value(libraryProgressKey{}).(libraryProgressFunc); ok && (done || len(items) > 0) {
+		return callback(source, items, err, done)
+	}
+	return nil
+}
+
+func (a *UIApp) setLibraryPhaseLocked(phase string) {
+	phase = strings.TrimSpace(phase)
+	a.libraryLoadingPhase = phase
+	if a.librarySources == nil {
+		a.librarySources = map[string]librarySourceState{}
+	}
+	for source, state := range a.librarySources {
+		if state.Status == "loading" {
+			a.librarySources[source] = state.withPhase(phase)
+		}
+	}
+}
+
+func (a *UIApp) handleLibraryCancel(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		writeJSON(w, http.StatusMethodNotAllowed, map[string]string{"error": "method not allowed"})
+		return
+	}
+	a.mu.Lock()
+	cancel := a.libraryCancel
+	running := a.libraryLoading != nil
+	if running {
+		a.setLibraryPhaseLocked("正在停止，已保留已入库内容")
+		a.libraryRevision++
+	}
+	resp := a.librarySnapshotForSourceLocked(r.Context(), 0)
+	a.mu.Unlock()
+	if cancel != nil {
+		cancel()
+	}
+	resp["canceled"] = running
+	writeJSON(w, http.StatusOK, resp)
+}
+
+func (a *UIApp) startLibraryRefreshLocked(source string) {
+	a.startLibraryLoadLocked(source, libraryLoadRefresh, nil, "")
+}
+
+func (a *UIApp) startLibraryLoadLocked(source string, mode libraryLoadMode, priority []string, category string, scopes ...context.Context) {
+	category = strings.TrimSpace(category)
+	base := context.Background()
+	if len(scopes) > 0 && sourceScope(scopes[0]) != nil {
+		base = context.WithValue(base, accountSourceContextKey{}, sourceScope(scopes[0]))
+	}
+	if mode == libraryLoadUpdate || mode == libraryLoadMore {
+		if source == "" && sourceScopeRestricted(base) {
+			for _, allowed := range sourceScope(base).Sources {
+				a.enqueueHistoricalMetadataLocked(allowed, priority)
+			}
+		} else {
+			a.enqueueHistoricalMetadataLocked(source, priority)
+		}
+	}
+	more := mode == libraryLoadMore
+	if more {
+		if !matchesSourceFilter(sourceHongguo, source) || !hongguoCatalogCategoryHasMore(a.libraryApp, category) {
+			return
+		}
+		source = sourceHongguo
+	}
+	previousCount := len(a.dramas)
+	a.libraryAttempted = true
+	a.libraryLoading = make(chan struct{})
+	a.libraryMore = more
+	a.libraryLoadingSource = source
+	a.libraryLoadingPhase = "等待开始"
+	if a.librarySources == nil {
+		a.librarySources = map[string]librarySourceState{}
+	}
+	for _, provider := range []string{sourceHongguo} {
+		if matchesSourceFilter(provider, source) {
+			state := a.librarySources[provider]
+			state.Status = "loading"
+			state.Error = ""
+			state.Phase = "等待开始"
+			a.librarySources[provider] = state
+		}
+	}
+	a.libraryRevision++
+	ctx, cancel := context.WithTimeout(base, 12*time.Minute)
+	a.libraryCancel = cancel
+	ctx = context.WithValue(ctx, libraryProgressKey{}, libraryProgressFunc(a.acceptLibraryProgress))
+	ctx = context.WithValue(ctx, libraryMoreKey{}, more)
+	ctx = context.WithValue(ctx, libraryUpdateKey{}, mode == libraryLoadUpdate)
+	if category != "" {
+		ctx = context.WithValue(ctx, libraryCategoryKey{}, category)
+	}
+	ctx = withKnownHongguoDramas(ctx, a.dramas)
+	go func() {
+		defer cancel()
+		var loadErr error
+		a.mu.Lock()
+		a.setLibraryPhaseLocked("保存当前剧库")
+		a.libraryRevision++
+		a.mu.Unlock()
+		if err := a.persistLibraryIfDirty(); err != nil {
+			loadErr = err
+		} else if more {
+			a.mu.Lock()
+			a.setLibraryPhaseLocked("继续加载目录")
+			a.libraryRevision++
+			a.mu.Unlock()
+			items, err := a.downloader.fetchHongguoCategoryDramas(ctx, category)
+			loadErr = errors.Join(err, reportLibraryProgress(ctx, sourceHongguo, items, err, true))
+		} else {
+			a.mu.Lock()
+			a.setLibraryPhaseLocked("读取站源目录")
+			a.libraryRevision++
+			a.mu.Unlock()
+			_, loadErr = a.downloader.fetchAllDramas(ctx, source)
+		}
+		a.mu.Lock()
+		if ctx.Err() == context.Canceled {
+			loadErr = nil
+			a.markLibrarySourcesCanceledLocked(base, source)
+		} else if loadErr != nil && a.libraryLoading != nil {
+			a.markLibrarySourcesFailedLocked(base, source, loadErr)
+		}
+		a.libraryDirty = true
+		a.libraryRevision++
+		a.mu.Unlock()
+		_ = a.persistLibrary()
+		a.mu.Lock()
+		close(a.libraryLoading)
+		a.libraryLoading = nil
+		a.libraryCancel = nil
+		a.libraryLoadingPhase = ""
+		a.libraryRevision++
+		count := len(a.dramas)
+		a.mu.Unlock()
+		fmt.Printf("本地剧库：%d 部，本次新增 %d 部\n", count, count-previousCount)
+	}()
+}
+
+func (a *UIApp) persistLibraryIfDirty() error {
+	a.mu.Lock()
+	dirty := a.libraryDirty
+	a.mu.Unlock()
+	if !dirty {
+		return nil
+	}
+	return a.persistLibrary()
+}
+
+func (a *UIApp) markLibrarySourcesFailedLocked(ctx context.Context, source string, err error) {
+	if a.librarySources == nil {
+		a.librarySources = map[string]librarySourceState{}
+	}
+	if matchesSourceFilter(sourceHongguo, source) {
+		state := a.librarySources[sourceHongguo]
+		if state.Status == "loading" {
+			state.Status = "failed"
+			if state.Count > 0 {
+				state.Status = "partial"
+			}
+			state.Error = a.redactError(err)
+			state.Phase = ""
+			a.librarySources[sourceHongguo] = state
+		}
+	}
+	a.libraryError = librarySourceErrors(a.librarySources)
+}
+
+func (a *UIApp) markLibrarySourcesCanceledLocked(ctx context.Context, source string) {
+	if a.librarySources == nil {
+		a.librarySources = map[string]librarySourceState{}
+	}
+	for _, provider := range []string{sourceHongguo} {
+		if !matchesSourceFilter(provider, source) || !sourceAllowed(ctx, provider) {
+			continue
+		}
+		state := a.librarySources[provider]
+		if state.Status == "loading" {
+			state.Status = "canceled"
+			state.Error = ""
+			state.Phase = ""
+			a.librarySources[provider] = state
+		}
+	}
+	a.libraryError = librarySourceErrors(a.librarySources)
+}
+
+func (a *UIApp) acceptLibraryProgress(source string, items []Drama, loadErr error, done bool) error {
+	if canonicalProviderSource(source) != sourceHongguo {
+		return nil
+	}
+	source = sourceHongguo
+	a.mu.Lock()
+	items = onlyHongguoDramas(items)
+	a.normalizeDramaCovers(items)
+	newDramas := a.newSortMetadataDramasLocked(items)
+	if source == sourceHongguo {
+		a.libraryApp = a.downloader.hongguoCatalogSnapshot()
+	}
+	if done {
+		var mergeErr error
+		if loadErr != nil {
+			mergeErr = &libraryLoadError{failures: map[string]error{source: loadErr}}
+		}
+		a.dramas = mergeSourceDramas(a.dramas, items, mergeErr, source)
+	} else {
+		positions := make(map[string]int, len(a.dramas))
+		for index, drama := range a.dramas {
+			positions[drama.ID] = index
+		}
+		for _, drama := range items {
+			if drama.ID == "" {
+				continue
+			}
+			if position, found := positions[drama.ID]; found {
+				a.dramas[position] = mergeDramaMetadata(drama, a.dramas[position])
+			} else {
+				positions[drama.ID] = len(a.dramas)
+				a.dramas = append(a.dramas, drama)
+			}
+		}
+	}
+	a.enqueueSortMetadataLocked(newDramas, false)
+	state := a.librarySources[source]
+	state.Count = 0
+	for _, drama := range a.dramas {
+		if dramaProvider(drama) == source {
+			state.Count++
+		}
+	}
+	if len(items) > 0 {
+		a.loadedAt = time.Now()
+		state.UpdatedAt = a.loadedAt
+	}
+	if done {
+		state.Status = "ready"
+		if loadErr != nil {
+			state.Status = "failed"
+			if state.Count > 0 {
+				state.Status = "partial"
+			}
+			state.Error = a.redactError(loadErr)
+		}
+		state.Phase = ""
+	}
+	a.librarySources[source] = state
+	a.libraryError = librarySourceErrors(a.librarySources)
+	a.libraryDirty = true
+	a.libraryRevision++
+	persist := done || len(items) > 0 && source == sourceHongguo || time.Since(a.libraryLastSave) >= 3*time.Second
+	if persist {
+		a.libraryLastSave = time.Now()
+	}
+	a.mu.Unlock()
+	if persist {
+		return a.persistLibrary()
+	}
+	return nil
+}
+
+func librarySourceErrors(sources map[string]librarySourceState) string {
+	var messages []string
+	for source, state := range sources {
+		if state.Error != "" {
+			messages = append(messages, fmt.Sprintf("%s 获取失败: %s", source, state.Error))
+		}
+	}
+	sort.Strings(messages)
+	return strings.Join(messages, "\n")
+}
+
+func cloneLibrarySources(sources map[string]librarySourceState) map[string]librarySourceState {
+	copy := make(map[string]librarySourceState, len(sources))
+	for source, state := range sources {
+		copy[source] = state
+	}
+	return copy
+}
+
+func (a *UIApp) persistLibrary() error {
+	a.libraryWriteMu.Lock()
+	defer a.libraryWriteMu.Unlock()
+	a.mu.Lock()
+	cache := libraryCache{Dramas: append([]Drama{}, a.dramas...), LoadedAt: a.loadedAt, LastError: librarySourceErrors(a.librarySources), Sources: cloneLibrarySources(a.librarySources), HongguoApp: cloneHongguoCatalogState(a.libraryApp)}
+	revision := a.libraryRevision
+	a.mu.Unlock()
+	err := writeLibraryCache(a.cfg.dataDirectory(), cache)
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	if err != nil {
+		a.libraryError = strings.TrimSpace(cache.LastError + "\n剧库缓存保存失败: " + a.redactError(err))
+		a.libraryRevision++
+		return err
+	}
+	a.librarySaved = true
+	if revision == a.libraryRevision {
+		a.libraryDirty = false
+	}
+	return nil
+}
+
+func (a *UIApp) librarySnapshotLocked(revision uint64) map[string]any {
+	remaining := sortMetadataRemaining(a.dramas)
+	var unqueued []Drama
+	for _, drama := range a.dramas {
+		if !a.metadataPending[drama.ID] {
+			unqueued = append(unqueued, drama)
+		}
+	}
+	more := map[string]bool{}
+	for source, count := range sortMetadataRemaining(unqueued) {
+		more[source] = count > 0
+	}
+	more["hongguo"] = more["hongguo"] || hongguoCatalogHasMore(a.libraryApp)
+	more[""] = more[""] || more["hongguo"]
+	response := map[string]any{
+		"revision": a.libraryRevision, "loadedAt": a.loadedAt, "loading": a.libraryLoading != nil,
+		"cached": a.librarySaved && !a.libraryDirty, "error": a.libraryError,
+		"sources": cloneLibrarySources(a.librarySources), "total": len(a.dramas),
+		"hasMore": more["hongguo"], "hasMoreBySource": more, "metadataRemaining": remaining,
+		"loadingMore": a.libraryMore && a.libraryLoading != nil, "loadingSource": a.libraryLoadingSource, "loadingPhase": a.libraryLoadingPhase, "metadata": a.libraryMetadata,
+	}
+	if revision != 0 && revision == a.libraryRevision {
+		response["unchanged"] = true
+	} else {
+		response["data"] = append([]Drama{}, a.dramas...)
+	}
+	return response
+}
diff --git a/internal/app/library_update_test.go b/internal/app/library_update_test.go
new file mode 100644
index 0000000..6e16c12
--- /dev/null
+++ b/internal/app/library_update_test.go
@@ -0,0 +1,322 @@
+package app
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"reflect"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func TestUnifiedUpdateChecksNewContentAndContinuesCatalog(t *testing.T) {
+	for _, test := range []struct {
+		name          string
+		pages         int
+		savedOffset   int
+		savedEnd      bool
+		knownOffsets  []int
+		endAt         int
+		wantOffsets   []int
+		wantSaved     int
+		wantEnd       bool
+		resumeSession bool
+	}{
+		{name: "first import runs one batch", pages: 2, endAt: -1, wantOffsets: []int{0, 18}, wantSaved: 36},
+		{name: "known head resumes saved tail", pages: 2, savedOffset: 90, knownOffsets: []int{0}, endAt: -1, wantOffsets: []int{0, 90, 108}, wantSaved: 126, resumeSession: true},
+		{name: "new head stops at overlap", pages: 4, savedOffset: 90, knownOffsets: []int{18}, endAt: -1, wantOffsets: []int{0, 18, 90, 108, 126, 144}, wantSaved: 162, resumeSession: true},
+		{name: "large update continues next unread page", pages: 4, savedOffset: 180, endAt: -1, wantOffsets: []int{0, 18, 36, 54, 72, 90, 108}, wantSaved: 126},
+		{name: "exhausted catalog still checks new content", pages: 4, savedOffset: 180, savedEnd: true, knownOffsets: []int{18}, endAt: -1, wantOffsets: []int{0, 18}, wantSaved: 180, wantEnd: true},
+		{name: "continuation reaches end", pages: 2, savedOffset: 90, knownOffsets: []int{0}, endAt: 90, wantOffsets: []int{0, 90}, wantSaved: 108, wantEnd: true, resumeSession: true},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			calls := map[string][]int{}
+			var known []Drama
+			for index := range hongguoAppGenres {
+				for _, offset := range test.knownOffsets {
+					known = append(known, Drama{ID: fmt.Sprintf("hongguo:%d", 790000+index*1000+offset), Source: sourceHongguo})
+				}
+			}
+			d := rankingTestDownloader(t, func(request *http.Request) (*http.Response, error) {
+				var payload struct {
+					Offset  int    `json:"offset"`
+					Session string `json:"session_id"`
+					Select  struct {
+						Genre []string `json:"genre"`
+					} `json:"select_items"`
+				}
+				if request.URL.Path != "/reading/distribution/category/landpage/v/" || json.NewDecoder(request.Body).Decode(&payload) != nil || len(payload.Select.Genre) != 1 {
+					t.Errorf("unexpected catalog request: %s", request.URL.Path)
+					return rankingHTTPResponse(request, 400, ""), nil
+				}
+				genre := payload.Select.Genre[0]
+				index := -1
+				for position, candidate := range hongguoAppGenres {
+					if candidate.key == genre {
+						index = position
+					}
+				}
+				if index < 0 {
+					t.Errorf("unexpected genre: %s", genre)
+					return rankingHTTPResponse(request, 400, ""), nil
+				}
+				calls[genre] = append(calls[genre], payload.Offset)
+				if payload.Offset == 0 && payload.Session != "" {
+					t.Error("head check reused a tail session")
+				}
+				if test.resumeSession && payload.Offset == test.savedOffset && payload.Session != "saved-"+genre {
+					t.Error("continuation lost its saved session")
+				}
+				body, _ := json.Marshal(map[string]any{"data": map[string]any{
+					"next_offset": payload.Offset + 18, "session_id": "fixture-" + genre, "has_more": payload.Offset != test.endAt,
+					"video_data": []any{map[string]any{
+						"series_id": fmt.Sprint(790000 + index*1000 + payload.Offset), "series_title": "文字目录样本",
+						"first_visible_time": "1773662280", "hot_score": "20", "series_play_cnt": "0",
+					}},
+				}})
+				return rankingHTTPResponse(request, 200, string(body)), nil
+			})
+			d.cfg.MaxPagesPerSort = test.pages
+			if test.savedOffset > 0 {
+				client := d.hongguoClient()
+				for _, genre := range hongguoAppGenres {
+					client.state.Feeds[genre.key] = hongguoCatalogCursor{
+						Offset: test.savedOffset, SessionID: "saved-" + genre.key, Initialized: true, Exhausted: test.savedEnd, UpdatedAt: time.Now(),
+					}
+				}
+			}
+			ctx := withKnownHongguoDramas(context.WithValue(context.Background(), libraryUpdateKey{}, true), known)
+			items, err := d.fetchHongguoAppCatalog(ctx)
+			if err != nil || len(items) != len(test.wantOffsets)*len(hongguoAppGenres) {
+				t.Fatalf("catalog result: %d items, %v", len(items), err)
+			}
+			for _, genre := range hongguoAppGenres {
+				if !reflect.DeepEqual(calls[genre.key], test.wantOffsets) {
+					t.Errorf("%s requested %v, want %v", genre.key, calls[genre.key], test.wantOffsets)
+				}
+				cursor := d.hongguoCatalogSnapshot().Feeds[genre.key]
+				if !cursor.Initialized || cursor.Offset != test.wantSaved || cursor.Exhausted != test.wantEnd {
+					t.Errorf("wrong checkpoint for %s: %+v", genre.key, cursor)
+				}
+			}
+		})
+	}
+}
+
+func TestUnifiedUpdatePreservesHistoryAcrossRestart(t *testing.T) {
+	calls := map[string][]int{}
+	transport := func(request *http.Request) (*http.Response, error) {
+		var payload struct {
+			Offset int    `json:"offset"`
+			Scene  string `json:"req_scene"`
+		}
+		if request.URL.Path != "/reading/distribution/category/landpage/v/" || json.NewDecoder(request.Body).Decode(&payload) != nil {
+			t.Errorf("unexpected request: %s", request.URL.Path)
+			return rankingHTTPResponse(request, 400, ""), nil
+		}
+		calls[payload.Scene] = append(calls[payload.Scene], payload.Offset)
+		index := 0
+		for position, genre := range hongguoAppGenres {
+			if genre.scene == payload.Scene {
+				index = position
+			}
+		}
+		body := fmt.Sprintf(`{"data":{"next_offset":%d,"has_more":%t,"session_id":"saved-session","video_data":[{"series_id":"%d","series_title":"文字样本","first_visible_time":"1773662280","hot_score":"20","series_play_cnt":"0"}]}}`, payload.Offset+18, payload.Offset == 0, 790000+index*1000+payload.Offset)
+		return rankingHTTPResponse(request, 200, body), nil
+	}
+	directory := t.TempDir()
+	for run, wantCount := range []int{3, 6, 6} {
+		d := rankingTestDownloader(t, transport)
+		d.cfg.dataDir, d.cfg.MaxPagesPerSort = directory, 1
+		items, err := d.RefreshDramas(context.WithValue(context.Background(), libraryUpdateKey{}, true), sourceHongguo)
+		if err != nil || len(items) != wantCount {
+			t.Fatalf("run %d lost history: %d items, %v", run, len(items), err)
+		}
+		cache, err := readLibraryCache(directory)
+		if err != nil || len(cache.Dramas) != wantCount || hongguoCatalogHasMore(cache.HongguoApp) != (run == 0) {
+			t.Fatalf("run %d did not persist data and cursor together: %v", run, err)
+		}
+		for _, drama := range cache.Dramas {
+			if drama.OnlineDate != "2026-03-16" || drama.Heat != "20" || drama.Views != "0" {
+				t.Fatal("update lost available sorting fields")
+			}
+		}
+	}
+	for scene, offsets := range calls {
+		if !reflect.DeepEqual(offsets, []int{0, 0, 18, 0}) {
+			t.Errorf("%s skipped or repeated a continuation: %v", scene, offsets)
+		}
+	}
+}
+
+func TestUnifiedUpdateReturnsImmediatelyAndDeduplicatesWork(t *testing.T) {
+	catalogStarted, catalogRelease := make(chan struct{}), make(chan struct{})
+	detailStarted, detailRelease := make(chan string, 1), make(chan struct{})
+	releaseCatalog := sync.OnceFunc(func() { close(catalogRelease) })
+	releaseDetail := sync.OnceFunc(func() { close(detailRelease) })
+	var catalogOnce sync.Once
+	var catalogCalls atomic.Int32
+	var detailMu sync.Mutex
+	var detailIDs []string
+	d := rankingTestDownloader(t, func(request *http.Request) (*http.Response, error) {
+		switch request.URL.Path {
+		case "/reading/distribution/category/landpage/v/":
+			catalogCalls.Add(1)
+			catalogOnce.Do(func() { close(catalogStarted) })
+			select {
+			case <-catalogRelease:
+			case <-request.Context().Done():
+				return nil, request.Context().Err()
+			}
+			return rankingHTTPResponse(request, 200, `{"data":{"next_offset":18,"has_more":false,"video_data":[{"series_id":"790000","series_title":"已完成的目录条目","first_visible_time":"1773662280","hot_score":"20","series_play_cnt":"0"}]}}`), nil
+		case "/detail":
+			if request.Context().Value(backgroundCatalogKey{}) != true {
+				t.Error("historical metadata did not use background priority")
+			}
+			id := request.URL.Query().Get("series_id")
+			detailMu.Lock()
+			detailIDs = append(detailIDs, id)
+			if len(detailIDs) == 1 {
+				detailStarted <- id
+			}
+			detailMu.Unlock()
+			select {
+			case <-detailRelease:
+			case <-request.Context().Done():
+				return nil, request.Context().Err()
+			}
+			return rankingHTTPResponse(request, 200, sortDetailFixture(id, "1773662280")), nil
+		default:
+			t.Errorf("unexpected resource: %s", request.URL.Path)
+			return rankingHTTPResponse(request, 404, ""), nil
+		}
+	})
+	d.cfg.MaxPagesPerSort = 1
+	for _, genre := range hongguoAppGenres {
+		d.hongguoClient().state.Feeds[genre.key] = hongguoCatalogCursor{Initialized: true, Exhausted: true, Offset: 18}
+	}
+	app := &UIApp{downloader: d, cfg: d.cfg, libraryAttempted: true, libraryApp: d.hongguoCatalogSnapshot(), librarySources: map[string]librarySourceState{}}
+	app.dramas = append(app.dramas, Drama{ID: "hongguo:790000", Source: sourceHongguo, Title: "已完成的目录条目", OnlineDate: "2026-03-16", Heat: "20", Views: "0", Cover: coverAddressFixture, SortMetadata: &sortMetadataState{Version: sortMetadataVersion}})
+	for index := 0; index < 60; index++ {
+		app.dramas = append(app.dramas, Drama{ID: fmt.Sprintf("hongguo:%d", 800000+index), Source: sourceHongguo, Title: "历史文字样本", Heat: "20", Views: "0", Cover: coverAddressFixture})
+	}
+	t.Cleanup(func() {
+		releaseCatalog()
+		releaseDetail()
+		app.mu.Lock()
+		done, cancel := app.libraryLoading, app.libraryCancel
+		app.mu.Unlock()
+		if cancel != nil {
+			cancel()
+		}
+		if done != nil {
+			select {
+			case <-done:
+			case <-time.After(3 * time.Second):
+				t.Error("catalog worker did not stop")
+			}
+		}
+		app.stopSortMetadata()
+	})
+	type snapshot struct {
+		Accepted bool                    `json:"updateAccepted"`
+		Loading  bool                    `json:"loading"`
+		Data     []Drama                 `json:"data"`
+		Metadata libraryMetadataProgress `json:"metadata"`
+	}
+	read := func(path string) snapshot {
+		t.Helper()
+		done := make(chan *httptest.ResponseRecorder, 1)
+		go func() {
+			writer := httptest.NewRecorder()
+			app.handleDramas(writer, httptest.NewRequest("GET", path, nil))
+			done <- writer
+		}()
+		select {
+		case writer := <-done:
+			var result snapshot
+			if writer.Code != 200 || json.Unmarshal(writer.Body.Bytes(), &result) != nil {
+				t.Fatalf("invalid snapshot: %d %s", writer.Code, writer.Body.String())
+			}
+			return result
+		case <-time.After(2 * time.Second):
+			t.Fatal("library response waited for a stalled upstream request")
+			return snapshot{}
+		}
+	}
+	if result := read("/api/ui/dramas"); result.Loading || result.Metadata.Total != 0 || catalogCalls.Load() != 0 {
+		t.Fatal("ordinary cache read scheduled remote work")
+	}
+	path := "/api/ui/dramas?update=1&source=hongguo&priority=hongguo:800059"
+	result := read(path)
+	if !result.Accepted || !result.Loading || result.Metadata.Total != 40 || len(result.Data) != 61 {
+		t.Fatalf("update did not immediately return cache and bounded progress: %+v", result.Metadata)
+	}
+	select {
+	case <-catalogStarted:
+	case <-time.After(2 * time.Second):
+		t.Fatal("update did not start the main catalog")
+	}
+	for _, request := range []string{path, path, "/api/ui/dramas?revision=1"} {
+		if result := read(request); result.Accepted || !result.Loading || result.Metadata.Total != 40 {
+			t.Fatal("repeated update or polling duplicated work")
+		}
+	}
+	select {
+	case <-detailStarted:
+		t.Fatal("metadata did not yield to the catalog")
+	default:
+	}
+	app.mu.Lock()
+	catalogDone := app.libraryLoading
+	app.mu.Unlock()
+	releaseCatalog()
+	select {
+	case <-catalogDone:
+	case <-time.After(2 * time.Second):
+		t.Fatal("catalog waited for optional metadata")
+	}
+	select {
+	case id := <-detailStarted:
+		if id != "800059" {
+			t.Fatalf("current filtered result was not prioritized: %s", id)
+		}
+	case <-time.After(2 * time.Second):
+		t.Fatal("historical metadata was not scheduled")
+	}
+	if result := read("/api/ui/dramas"); result.Loading || !result.Metadata.Running || result.Metadata.Checked != 0 || catalogCalls.Load() != 3 {
+		t.Fatal("optional metadata blocked the main response or catalog work was duplicated")
+	}
+	releaseDetail()
+	waitSortMetadataQueue(t, app)
+	result = read("/api/ui/dramas")
+	if result.Metadata.Checked != 40 || result.Metadata.Failed != 0 || result.Metadata.Running {
+		t.Fatalf("unexpected completion: %+v", result.Metadata)
+	}
+	untouched := 0
+	for _, drama := range result.Data {
+		if strings.HasPrefix(drama.ID, "hongguo:800") && drama.SortMetadata == nil {
+			untouched++
+		}
+	}
+	if untouched != 20 {
+		t.Fatalf("update migrated more than one historical batch: %d untouched", untouched)
+	}
+	detailMu.Lock()
+	defer detailMu.Unlock()
+	seen := map[string]bool{}
+	for _, id := range detailIDs {
+		if seen[id] {
+			t.Fatalf("duplicate historical request: %s", id)
+		}
+		seen[id] = true
+	}
+	if len(seen) != 40 {
+		t.Fatalf("unexpected detail request count: %d", len(seen))
+	}
+}
diff --git a/internal/app/media_crypto.go b/internal/app/media_crypto.go
new file mode 100644
index 0000000..54e60b4
--- /dev/null
+++ b/internal/app/media_crypto.go
@@ -0,0 +1,21 @@
+package app
+
+import (
+	"errors"
+)
+
+func pkcs7Unpad(src []byte, blockSize int) ([]byte, error) {
+	if len(src) == 0 || len(src)%blockSize != 0 {
+		return nil, errors.New("invalid pkcs7 length")
+	}
+	pad := int(src[len(src)-1])
+	if pad == 0 || pad > blockSize || pad > len(src) {
+		return nil, errors.New("invalid pkcs7 padding")
+	}
+	for _, v := range src[len(src)-pad:] {
+		if int(v) != pad {
+			return nil, errors.New("invalid pkcs7 padding bytes")
+		}
+	}
+	return src[:len(src)-pad], nil
+}