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/strm_queue_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"testing"
+	"time"
 
 	"github.com/ShukeBta/MMTL/internal/model"
 	"github.com/ShukeBta/MMTL/internal/repository"
@@ -104,3 +105,62 @@ func TestStrmUploadTasksClearAndRetry(t *testing.T) {
 		t.Fatalf("expected 2 remaining tasks, got %d", count)
 	}
 }
+
+func TestDownloadSemSeparateByProvider(t *testing.T) {
+	svc := NewStrmService(nil, zap.NewNop(), nil, nil)
+	svc.initDownloadSems(6)
+
+	if cap(svc.downloadSem115) != strm115DownloadSemCap {
+		t.Fatalf("115 sem cap = %d, want %d", cap(svc.downloadSem115), strm115DownloadSemCap)
+	}
+	if cap(svc.downloadSemDAV) != 6 {
+		t.Fatalf("dav sem cap = %d, want 6", cap(svc.downloadSemDAV))
+	}
+
+	ctx := context.Background()
+	for i := 0; i < strm115DownloadSemCap; i++ {
+		if !svc.acquireDownloadSlot(ctx, model.StrmProvider115) {
+			t.Fatalf("failed to acquire 115 slot %d", i)
+		}
+	}
+	// 115 槽位占满后，OpenList 仍应能独立获取槽位。
+	if !svc.acquireDownloadSlot(ctx, model.StrmProviderOpenList) {
+		t.Fatal("openlist slot should remain available while 115 slots are full")
+	}
+	for i := 0; i < 5; i++ {
+		if !svc.acquireDownloadSlot(ctx, model.StrmProviderOpenList) {
+			t.Fatalf("failed to acquire extra openlist slot %d", i)
+		}
+	}
+	timeoutCtx, cancel := context.WithTimeout(ctx, 50*time.Millisecond)
+	defer cancel()
+	if svc.acquireDownloadSlot(timeoutCtx, model.StrmProviderOpenList) {
+		t.Fatal("expected openlist slots to be exhausted after 6 acquisitions")
+	}
+}
+
+func TestRequeueDownloadTask(t *testing.T) {
+	db := newServiceTestDB(t, &model.StrmDownloadTask{})
+	repos := repository.New(db)
+	svc := NewStrmService(nil, zap.NewNop(), repos, nil)
+	now := time.Now()
+	task := &model.StrmDownloadTask{
+		Base:      model.Base{ID: "dl-running"},
+		Status:    model.StrmTaskRunning,
+		Provider:  model.StrmProviderOpenList,
+		StartedAt: &now,
+	}
+	if err := db.Create(task).Error; err != nil {
+		t.Fatalf("insert task: %v", err)
+	}
+
+	svc.requeueDownloadTask(task)
+
+	var got model.StrmDownloadTask
+	if err := db.First(&got, "id = ?", task.ID).Error; err != nil {
+		t.Fatalf("load task: %v", err)
+	}
+	if got.Status != model.StrmTaskPending || got.StartedAt != nil {
+		t.Fatalf("task not requeued: %+v", got)
+	}
+}