feat(sdk): add RegisterStopHandler/RunStopHandlers and wire stop cleanup into registry lifecycle

- SDK PluginSDK gains RegisterStopHandler(fn func()) + RunStopHandlers()
  (LIFO, idempotent, cleared after running); synced to third_party copy
- Registry keeps per-plugin SDK refs (sdkRefs); StopAll/ReloadOne/
  DisablePlugin run handlers before calling Stop()
- timer built-in plugin demonstrates handler-based shutdown cleanup
- z_bridge (linux/windows templates) runs handlers before plugin.Stop()

internal/plugins/timer/plugin.go

@@ -42,6 +42,8 @@ func (p *Plugin) Name() string { return p.name }
 func (p *Plugin) Start(s *sdk.PluginSDK) error {
 	s.SetAutoRestart(true)
 	p.maxDur = 24 * time.Hour
+	// 停止清理（取消倒计时）交由 stop handler：内核在调用 Stop() 之前执行。
+	s.RegisterStopHandler(func() { close(p.stopCh) })
 	s.Settings().RegisterDef(sdk.ConfigDef{
 		Key: "max_duration", Type: "string", DisplayName: "最大定时时长",
 		Description: "允许设置的最大定时时长，例如 24h, 7d, 1h（默认 24h）",
@@ -118,7 +120,6 @@ func (p *Plugin) Start(s *sdk.PluginSDK) error {
 }
 
 func (p *Plugin) Stop() error {
-	close(p.stopCh)
 	p.wg.Wait()
 	return nil
 }

internal/plugins/webui/dashboard.html

@@ -258,9 +258,11 @@ code { font-family:monospace; font-size:12px; color:var(--pre-color) }
   .msg { max-width:95% }
 }
 @media(max-width:768px) {
-  nav { padding:0 8px; gap:2px }
-  nav h1 { font-size:13px; margin-right:8px }
-  nav a { padding:8px 6px; font-size:11px }
+  nav { padding:0 6px; gap:2px; overflow-x:auto; scrollbar-width:none; -ms-overflow-style:none; flex-wrap:nowrap }
+  nav::-webkit-scrollbar { display:none }
+  nav h1 { font-size:0; margin-right:6px; color:var(--accent) }
+  nav a { padding:10px 8px; font-size:12px; white-space:nowrap; flex-shrink:0 }
+  nav > div { flex-shrink:0 }
   .container { padding:12px }
   .card { padding:12px }
   .grid-2,.grid-3,.grid-4 { grid-template-columns:1fr }