[client] Add Wails3 + React desktop UI scaffold

Stage 1 of the client/ui (Fyne) replacement. Adds a new client/ui-wails
module that runs on Linux/macOS/Windows from a single React + Vite +
Tailwind frontend driven by a thin gRPC services layer in Go.

- Single-module integration (no submodule): merge Wails3 into root go.mod
  with build tags !android !ios !freebsd !js so cross-compiles on those
  targets exclude the package automatically.
- Seven gRPC-bound services: Connection, Settings, Networks, Profiles,
  Debug, Update, Peers. Peers bridges Status polling and SubscribeEvents
  to the Wails event bus (netbird:status, netbird:event).
- Tray + window shell mirrors the Fyne menu 1:1 with hide-on-close,
  SIGUSR1 / Windows named-event for external "show window" triggers.
- React pages cover functional parity for Status, Settings (3 tabs),
  Networks (3 tabs), Profiles, Debug, Update, QuickActions, LoginUrl.
- SVG-sourced tray icons (12 source SVGs incl. macOS template variants)
  rasterized to PNG via task common:generate:tray:icons.
- Linux launcher sets WEBKIT_DISABLE_DMABUF_RENDERER=1 in the .desktop
  Exec= line and in task linux:run so the app renders correctly under
  RDP, VirtualBox, KVM, and bare WMs (Fluxbox/dwm) without DRM access.

client/ui-wails/main.go

@@ -0,0 +1,101 @@
+//go:build !android && !ios && !freebsd && !js
+
+package main
+
+import (
+	"context"
+	"embed"
+	"flag"
+	"log"
+
+	"github.com/wailsapp/wails/v3/pkg/application"
+	"github.com/wailsapp/wails/v3/pkg/events"
+	"github.com/wailsapp/wails/v3/pkg/services/notifications"
+
+	"github.com/netbirdio/netbird/client/ui-wails/services"
+)
+
+//go:embed all:frontend/dist
+var assets embed.FS
+
+func init() {
+	application.RegisterEvent[services.Status](services.EventStatus)
+	application.RegisterEvent[services.SystemEvent](services.EventSystem)
+	application.RegisterEvent[services.UpdateAvailable](services.EventUpdateAvailable)
+	application.RegisterEvent[services.UpdateProgress](services.EventUpdateProgress)
+}
+
+func main() {
+	daemonAddr := flag.String("daemon-addr", DaemonAddr(), "Daemon gRPC address: unix:///path or tcp://host:port")
+	flag.Parse()
+
+	conn := NewConn(*daemonAddr)
+
+	// tray is captured in the SingleInstance callback below; the var is
+	// declared before app.New so the closure has a stable reference.
+	var tray *Tray
+
+	app := application.New(application.Options{
+		Name:        "netbird-ui",
+		Description: "NetBird desktop client",
+		Assets: application.AssetOptions{
+			Handler: application.AssetFileServerFS(assets),
+		},
+		Mac: application.MacOptions{
+			ApplicationShouldTerminateAfterLastWindowClosed: false,
+		},
+		SingleInstance: &application.SingleInstanceOptions{
+			UniqueID: "io.netbird.ui",
+			OnSecondInstanceLaunch: func(_ application.SecondInstanceData) {
+				if tray != nil {
+					tray.ShowWindow()
+				}
+			},
+		},
+	})
+
+	connection := services.NewConnection(conn)
+	settings := services.NewSettings(conn)
+	profiles := services.NewProfiles(conn)
+	peers := services.NewPeers(conn, app.Event)
+	notifier := notifications.New()
+
+	app.RegisterService(application.NewService(connection))
+	app.RegisterService(application.NewService(settings))
+	app.RegisterService(application.NewService(services.NewNetworks(conn)))
+	app.RegisterService(application.NewService(profiles))
+	app.RegisterService(application.NewService(services.NewDebug(conn)))
+	app.RegisterService(application.NewService(services.NewUpdate(conn)))
+	app.RegisterService(application.NewService(peers))
+	app.RegisterService(application.NewService(notifier))
+
+	window := app.Window.NewWithOptions(application.WebviewWindowOptions{
+		Title:            "NetBird",
+		Width:            960,
+		Height:           640,
+		Hidden:           false,
+		BackgroundColour: application.NewRGB(24, 26, 29),
+		URL:              "/",
+		Mac: application.MacWindow{
+			InvisibleTitleBarHeight: 38,
+			Backdrop:                application.MacBackdropTranslucent,
+			TitleBar:                application.MacTitleBarHiddenInset,
+		},
+	})
+
+	// Intercept the window close to hide instead of quit. The user reaches
+	// "really quit" via tray -> Quit.
+	window.RegisterHook(events.Common.WindowClosing, func(e *application.WindowEvent) {
+		e.Cancel()
+		window.Hide()
+	})
+
+	tray = NewTray(app, window, connection, settings, profiles, peers, notifier)
+	listenForShowSignal(context.Background(), tray)
+
+	peers.Watch(context.Background())
+
+	if err := app.Run(); err != nil {
+		log.Fatal(err)
+	}
+}