[management,client] 0.75.0 release with new desktop UI (#6473)

- **Wails v3 application** (`client/ui`) with a React + TypeScript + Tailwind frontend replacing the Fyne UI: main connection view, exit-node switcher, networks/peers browser with detail panels, profile management, settings (general, network, SSH, security, troubleshooting, appearance), debug-bundle creation, and a first-run welcome flow.
- **Internationalization**: go-i18n bundle with 9 locales (en, de, es, fr, hu, it, pt, ru, zh-CN) shared between the tray and the frontend.
- **New system tray** implementation with per-platform theme-aware icons, including a native XEmbed host for Linux (`xembed_tray_linux.c`) and a Linux theme watcher.
- **Session handling**: auth session watcher (`client/internal/auth/sessionwatch`), pending login flow, session-expiration dialog and tray notifications, and `netbird login` improvements.
- **Daemon API extensions** (`daemon.proto`): status stream subscription, event stream, networks/exit-node selection endpoints, and richer full status — with probe throttling on the daemon side to protect against UI-driven request storms.
- **UI preferences store** persisted per profile, autostart management via the daemon (single source of truth in HKCU on Windows).
- **Build system**: Taskfile-based builds per platform (macOS, Linux, Windows), Docker cross-compilation images, MSIX/NSIS/nfpm/AppImage packaging, and a new `frontend-ui` CI workflow.

Co-authored-by: Zoltan Papp <zoltan.pmail@gmail.com>
Co-authored-by: Eduard Gert <kontakt@eduardgert.de>
Co-authored-by: braginini <bangvalo@gmail.com>
Co-authored-by: Pascal Fischer <32096965+pascal-fischer@users.noreply.github.com>
Co-authored-by: riccardom <riccardomanfrin@gmail.com>

client/server/debug.go

@@ -53,7 +53,10 @@ func (s *Server) DebugBundle(_ context.Context, req *proto.DebugBundleRequest) (
 		if engine != nil {
 			refreshStatus = func() {
 				log.Debug("refreshing system health status for debug bundle")
-				engine.RunHealthProbes(true)
+				// Background ctx: the bundle wants a full, fresh probe regardless
+				// of the DebugBundle RPC client's lifetime. The engine's own ctx
+				// still aborts it on shutdown.
+				engine.RunHealthProbes(context.Background(), true)
 			}
 		}
 	}
@@ -64,6 +67,7 @@ func (s *Server) DebugBundle(_ context.Context, req *proto.DebugBundleRequest) (
 			StatusRecorder: s.statusRecorder,
 			SyncResponse:   syncResponse,
 			LogPath:        s.logFile,
+			UILogPath:      s.uiLogPath,
 			CPUProfile:     cpuProfileData,
 			CapturePath:    capturePath,
 			RefreshStatus:  refreshStatus,
@@ -124,9 +128,26 @@ func (s *Server) SetLogLevel(_ context.Context, req *proto.SetLogLevelRequest) (
 
 	log.Infof("Log level set to %s", level.String())
 
+	// Signal the desktop UI so it can attach/detach its gui-client.log. Rides
+	// the SubscribeEvents stream as a marked event (see publishLogLevelChanged).
+	s.publishLogLevelChanged(level.String())
+
 	return &proto.SetLogLevelResponse{}, nil
 }
 
+// RegisterUILog records the desktop UI's absolute log path so DebugBundle can
+// collect the GUI log. The daemon runs as root and can't resolve the user's
+// config dir, so the UI reports it. Last-writer-wins (one UI per socket).
+func (s *Server) RegisterUILog(_ context.Context, req *proto.RegisterUILogRequest) (*proto.RegisterUILogResponse, error) {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	s.uiLogPath = req.GetPath()
+	log.Infof("registered UI log path: %s", s.uiLogPath)
+
+	return &proto.RegisterUILogResponse{}, nil
+}
+
 // SetSyncResponsePersistence sets the sync response persistence for the server.
 func (s *Server) SetSyncResponsePersistence(_ context.Context, req *proto.SetSyncResponsePersistenceRequest) (*proto.SetSyncResponsePersistenceResponse, error) {
 	s.mutex.Lock()