fix(plugins): restore plugin runtimes on startup + graceful shutdown

Root cause: initVault() called Discover() but never called
SyncConfig(), InitRuntimes(), CallInitHooks(), or StartSchedulers().
On restart, plugins were discovered from disk but their config state
(Installed/Enabled) was not restored and no Lua VMs were created.

This caused:
- Settings → Plugins showing plugins as 'not installed' after restart
- Sidebar showing calendar item (from enabledSet config) but
  GetPluginPanelHTML failing (only checked p.Active)
- Toggle working in-session but state lost on restart
- closeVault() not stopping plugin schedulers/shutdown/VM (leak)

Fixes:
- bindings_config.go: add SyncConfig(appCfg) after Discover()
- bindings_config.go: add InitRuntimes() + CallInitHooks() + StartSchedulers()
  after watcher start
- bindings_config.go: add StopSchedulers + CallShutdownHooks + CloseRuntimes
  to closeVault() (before db.Close since plugins use DB)
- bindings_plugins.go: GetPluginPanelHTML now checks enabledSet || p.Active,
  consistent with ListSystemViewsWithPlugins and ListPlugins

cmd/verstak-gui/bindings_config.go

@@ -228,6 +228,9 @@ func (a *App) initVault(vaultPath string) error {
 		}
 	}
 
+	// Apply installed/enabled state from config to discovered plugins
+	pm.SyncConfig(appCfg)
+
 	// Sync service
 	deviceID := ""
 	_ = appCfg // will store sync settings
@@ -292,6 +295,11 @@ func (a *App) initVault(vaultPath string) error {
 	// Start auto-sync loop
 	go a.autoSyncLoop()
 
+	// Start plugin runtimes for enabled plugins (creates VM, loads scripts, calls on_init)
+	pm.InitRuntimes()
+	pm.CallInitHooks()
+	pm.StartSchedulers()
+
 	// Start bridge server for browser extension integration (if enabled).
 	if appCfg == nil || appCfg.Vault.Bridge.Enabled {
 		a.startBridge(appCfg)
@@ -313,6 +321,12 @@ func (a *App) closeVault() {
 	if a.fileWatcher != nil {
 		a.fileWatcher.Stop()
 	}
+	// Stop plugin runtimes (schedulers → on_shutdown → close VMs)
+	if a.plugins != nil {
+		a.plugins.StopSchedulers()
+		a.plugins.CallShutdownHooks()
+		a.plugins.CloseRuntimes()
+	}
 	// Stop bridge server.
 	if a.bridge != nil {
 		a.bridge.Stop()

cmd/verstak-gui/bindings_plugins.go

@@ -180,8 +180,16 @@ func (a *App) GetPluginPanelHTML(pluginName string) (string, error) {
 	if a.plugins == nil {
 		return "", fmt.Errorf("plugin manager not ready")
 	}
+	appCfg, _ := config.LoadAppConfig()
+	enabledSet := make(map[string]bool)
+	if appCfg != nil {
+		for _, name := range appCfg.EnabledPlugins {
+			enabledSet[name] = true
+		}
+	}
 	for _, p := range a.plugins.Plugins() {
-		if p.Meta.Name != pluginName || !p.Active {
+		active := enabledSet[p.Meta.Name] || p.Active
+		if p.Meta.Name != pluginName || !active {
 			continue
 		}
 		if p.Meta.Panel == "" {