[client] Create GUI windows on demand and destroy them on close (#7096)

The main and Settings windows were created at startup and kept alive hidden on close, so an idle tray held two webview processes for surfaces the user may never open. Both are now built on first show and destroyed on close, which takes the idle footprint on macOS from ~160 MB to ~74 MB.

The WindowManager owns creation: it rebuilds the main window on the next show and hands out live pointers, since a stored one goes stale. Every show is deferred until the frontend reports it has rendered, so a freshly created window is never on screen empty, with a timeout so a frontend that never reports cannot strand a window hidden.

client/ui/main.go

@@ -139,13 +139,11 @@ func main() {
 		prefStore:       prefStore,
 	})
 
-	window := newMainWindow(app, prefStore)
-
-	// Settings is created eagerly (hidden) so the first gear click paints
-	// instantly and React keeps per-tab state across reopens. The other
-	// auxiliary windows stay lazy + destroy-on-close so Wails's macOS
-	// dock-reopen handler can't resurrect them.
-	windowManager := services.NewWindowManager(app, window, bundle, prefStore, iconWindow)
+	windowManager := services.NewWindowManager(app, nil, bundle, prefStore, iconWindow)
+	windowManager.SetMainFactory(func(startURL string) *application.WebviewWindow {
+		return newMainWindow(app, prefStore, windowManager, startURL)
+	})
+	registerDockReopenHook(app, windowManager)
 	// Minimal WMs (XEmbed-tray path) neither center small windows nor restore
 	// position across hide -> show, dropping them top-left. Gate Go-side
 	// re-centering on that environment; nil leaves placement to the WM on full
@@ -168,7 +166,7 @@ func main() {
 	// RegisterStatusNotifierItem hits a watcher we control.
 	startStatusNotifierWatcher()
 
-	tray = NewTray(app, window, TrayServices{
+	tray = NewTray(app, nil, TrayServices{
 		Connection:      connection,
 		Settings:        settings,
 		Profiles:        profiles,
@@ -279,10 +277,12 @@ func newApplication(onSecondInstance func()) *application.App {
 			ActivationPolicy: application.ActivationPolicyAccessory,
 		},
 		Linux: application.LinuxOptions{
-			ProgramName: "netbird",
+			ProgramName:                   "netbird",
+			DisableQuitOnLastWindowClosed: true,
 		},
 		Windows: application.WindowsOptions{
-			WndProcInterceptor: endSessionInterceptor(),
+			WndProcInterceptor:            endSessionInterceptor(),
+			DisableQuitOnLastWindowClosed: true,
 		},
 		SingleInstance: &application.SingleInstanceOptions{
 			UniqueID: "io.netbird.ui",
@@ -338,9 +338,7 @@ func registerServices(app *application.App, conn *Conn, s registeredServices) {
 	app.RegisterService(application.NewService(s.compat))
 }
 
-// newMainWindow creates the hidden main window, sized to the user's last view
-// mode, and installs the hide-on-close and macOS dock-reopen hooks.
-func newMainWindow(app *application.App, prefStore *preferences.Store) *application.WebviewWindow {
+func newMainWindow(app *application.App, prefStore *preferences.Store, wm *services.WindowManager, startURL string) *application.WebviewWindow {
 	// Width matches the last view mode so Advanced-mode users don't see the
 	// window pop from 380px to 900px on launch. Height is mode-agnostic.
 	initialWidth := 380
@@ -357,7 +355,7 @@ func newMainWindow(app *application.App, prefStore *preferences.Store) *applicat
 		InitialPosition:     application.WindowCentered,
 		Hidden:              true,
 		BackgroundColour:    services.WindowBackgroundColour,
-		URL:                 "/",
+		URL:                 startURL,
 		DisableResize:       true,
 		MinimiseButtonState: application.ButtonHidden,
 		MaximiseButtonState: application.ButtonHidden,
@@ -368,29 +366,25 @@ func newMainWindow(app *application.App, prefStore *preferences.Store) *applicat
 		},
 	})
 
-	// Hide instead of quit on close; "really quit" is reached via tray -> Quit.
-	window.RegisterHook(events.Common.WindowClosing, func(e *application.WindowEvent) {
+	window.RegisterHook(events.Common.WindowClosing, func(_ *application.WindowEvent) {
 		if services.ShuttingDown() {
 			return
 		}
-		e.Cancel()
-		window.Hide()
+		wm.ForgetMain()
 	})
 
-	// On macOS, Wails' default applicationShouldHandleReopen handler Show()s
-	// every hidden window on dock-icon click, resurrecting hide-on-close
-	// surfaces like Settings. Cancel it in a hook (hooks run before listeners)
-	// and show only the main window. No-op elsewhere — the event never fires.
-	if runtime.GOOS == "darwin" {
-		app.Event.RegisterApplicationEventHook(events.Mac.ApplicationShouldHandleReopen, func(e *application.ApplicationEvent) {
-			e.Cancel()
-			if e.Context().HasVisibleWindows() {
-				return
-			}
-			window.Show()
-			window.Focus()
-		})
-	}
-
 	return window
 }
+
+func registerDockReopenHook(app *application.App, wm *services.WindowManager) {
+	if runtime.GOOS != "darwin" {
+		return
+	}
+	app.Event.RegisterApplicationEventHook(events.Mac.ApplicationShouldHandleReopen, func(e *application.ApplicationEvent) {
+		if e.Context().HasVisibleWindows() {
+			return
+		}
+		e.Cancel()
+		wm.ShowMain()
+	})
+}