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/strm.go

@@ -29,6 +29,8 @@ type strmAccountView struct {
 	model.StrmAccount
 	HasCredential bool   `json:"has_credential"`
 	ProviderLabel string `json:"provider_label"`
+	// ConfigPreview 非敏感配置字段，供编辑表单回显。
+	ConfigPreview service.StrmAccountConfigPreview `json:"config_preview,omitempty"`
 	// ProxyPlay 仅远程 Emby 挂载账号返回：播放流量是否经过 MMTL 代理（编辑回显用）。
 	ProxyPlay *bool `json:"proxy_play,omitempty"`
 	// EmbyLines 仅远程 Emby 挂载账号返回：多线路配置（不含凭据）。
@@ -45,6 +47,9 @@ func strmAccountViews(svc *service.Container, accounts []model.StrmAccount) []st
 			HasCredential: service.HasStrmAccountCredential(&a),
 			ProviderLabel: providerLabelOf(a.Provider),
 		}
+		if svc != nil && svc.Strm != nil {
+			view.ConfigPreview = svc.Strm.StrmAccountConfigPreviewOf(&a)
+		}
 		if a.Provider == model.StrmProviderEmbyRemote && svc != nil && svc.EmbyRemote != nil {
 			if proxyPlay, err := svc.EmbyRemote.ProxyPlayOf(&a); err == nil {
 				view.ProxyPlay = &proxyPlay