[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/event.go

@@ -1,7 +1,9 @@
 package server
 
 import (
+	"github.com/google/uuid"
 	log "github.com/sirupsen/logrus"
+	"google.golang.org/protobuf/types/known/timestamppb"
 
 	"github.com/netbirdio/netbird/client/proto"
 )
@@ -16,6 +18,15 @@ func (s *Server) SubscribeEvents(req *proto.SubscribeRequest, stream proto.Daemo
 	log.Debug("client subscribed to events")
 	s.startUpdateManagerForGUI()
 
+	// Replay the current log level to this subscriber so a freshly-connected UI
+	// learns it even when the daemon was already started with --log-level debug
+	// (the change-driven publishLogLevelChanged only fires on SetLogLevel). Sent
+	// directly on this stream rather than via PublishEvent so it reaches only
+	// the new subscriber, not every connected client.
+	if err := s.sendCurrentLogLevel(stream); err != nil {
+		return err
+	}
+
 	for {
 		select {
 		case event := <-subscription.Events():
@@ -28,3 +39,24 @@ func (s *Server) SubscribeEvents(req *proto.SubscribeRequest, stream proto.Daemo
 		}
 	}
 }
+
+// sendCurrentLogLevel sends a marked log-level-changed SystemEvent carrying the
+// daemon's current level directly to one subscriber. Mirrors the shape
+// publishLogLevelChanged emits so the UI's dispatchSystemEvent handles both the
+// same way.
+func (s *Server) sendCurrentLogLevel(stream proto.DaemonService_SubscribeEventsServer) error {
+	level := log.GetLevel().String()
+	event := &proto.SystemEvent{
+		Id:        uuid.New().String(),
+		Severity:  proto.SystemEvent_INFO,
+		Category:  proto.SystemEvent_SYSTEM,
+		Message:   "Log level changed",
+		Metadata:  map[string]string{proto.MetadataKindKey: proto.MetadataKindLogLevelChanged, proto.MetadataLevelKey: level},
+		Timestamp: timestamppb.Now(),
+	}
+	if err := stream.Send(event); err != nil {
+		log.Warnf("error sending initial log level event: %v", err)
+		return err
+	}
+	return nil
+}