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/handler/playback_extra.go

@@ -82,6 +82,30 @@ func playbackProgressHandler(svc *service.Container) gin.HandlerFunc {
 	}
 }
 
+func playbackResumeHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		uid, _ := c.Get(middleware.CtxUserID)
+		row, err := svc.Playback.GetProgress(c.Request.Context(), toString(uid), c.Param("id"))
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+		if row == nil {
+			c.JSON(http.StatusOK, gin.H{
+				"position_ms": 0,
+				"duration_ms": 0,
+				"completed":   false,
+			})
+			return
+		}
+		c.JSON(http.StatusOK, gin.H{
+			"position_ms": row.PositionMs,
+			"duration_ms": row.DurationMs,
+			"completed":   row.Completed,
+		})
+	}
+}
+
 // externalPlayersHandler returns the list of external player URI
 // schemes the UI can offer the user. We lookup the media row to
 // produce the per-player launch URL.