perf(strm): 优化 OpenList 元数据下载速度 (#15)

* Add favourite buttons to library list and series detail pages

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

* Fix favourites list for remote Emby mounted media

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

* Route favourites to library series detail when appropriate

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

* Fix favourites link to library series for remote anime paths

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

* Fix remote Emby playback history and continue watching

- Preserve duration_ms when web player reports duration=0
- Add GET /playback/:id/resume for reliable per-item resume
- Switch home continue watching to /watch-history/continue API
- Set library_id on remote media for play-profile visibility
- Keep continue-watching rows when remote metadata hydration fails

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

* Fix mobile sort dropdown overflowing off-screen

Align dropdown to button left edge on small screens and cap width
to viewport so sort options stay fully visible on mobile.

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

* Remove stale Windows binary backup files

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

* Fix STRM account edit form not echoing saved config

Return config_preview from account API for server/url/username and
secret flags. Merge partial config updates so empty password/token
fields do not wipe stored credentials.

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

* perf(strm): speed up OpenList metadata downloads with provider-aware concurrency

- Split download semaphore: 115 stays capped at 3 for WAF safety; OpenList/CloudDrive2
  WebDAV metadata uses strm.download_threads (default raised to 6, max 16)
- Scope 115 WAF cooldown to 115 tasks only so OpenList downloads are not paused
- Requeue claimed tasks back to pending when slot acquisition fails or 115 is cooling
- Add tests for separate semaphores and requeue behavior

Co-authored-by: truewhile <truewhile@users.noreply.github.com>

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: truewhile <truewhile@users.noreply.github.com>

internal/service/playback_test.go

@@ -10,6 +10,53 @@ import (
 	"go.uber.org/zap"
 )
 
+func TestRecordProgressPreservesDurationWhenMissing(t *testing.T) {
+	db := newServiceTestDB(t, &model.PlaybackHistory{}, &model.Media{})
+	repos := repository.New(db)
+	userID := "user-1"
+	mediaID := "local-movie-1"
+	if err := db.Create(&model.PlaybackHistory{
+		Base:       model.Base{ID: "hist-1"},
+		UserID:     userID,
+		MediaID:    mediaID,
+		PositionMs: 30_000,
+		DurationMs: 120_000,
+		WatchedAt:  time.Now(),
+	}).Error; err != nil {
+		t.Fatalf("seed history: %v", err)
+	}
+
+	svc := NewPlaybackService(zap.NewNop(), repos)
+	if err := svc.RecordProgress(context.Background(), userID, mediaID, 60_000, 0); err != nil {
+		t.Fatalf("RecordProgress: %v", err)
+	}
+
+	var hist model.PlaybackHistory
+	if err := db.Where("user_id = ? AND media_id = ?", userID, mediaID).First(&hist).Error; err != nil {
+		t.Fatalf("find history: %v", err)
+	}
+	if hist.DurationMs != 120_000 {
+		t.Fatalf("expected duration preserved, got %d", hist.DurationMs)
+	}
+	if hist.PositionMs != 60_000 {
+		t.Fatalf("expected position updated, got %d", hist.PositionMs)
+	}
+}
+
+func TestGetProgressReturnsNilWhenMissing(t *testing.T) {
+	db := newServiceTestDB(t, &model.PlaybackHistory{})
+	repos := repository.New(db)
+	svc := NewPlaybackService(zap.NewNop(), repos)
+
+	row, err := svc.GetProgress(context.Background(), "user-1", "missing-media")
+	if err != nil {
+		t.Fatalf("GetProgress: %v", err)
+	}
+	if row != nil {
+		t.Fatalf("expected nil progress, got %#v", row)
+	}
+}
+
 func TestListFavouritesIncludesLocalAndRemoteIDs(t *testing.T) {
 	db := newServiceTestDB(t, &model.Favorite{}, &model.Media{})
 	repos := repository.New(db)