feat(ui): GUI debug logging follows daemon log level + debug bundle

When the daemon is set to debug/trace, the GUI now automatically writes a
rotated gui-client.log in the user's config dir and the daemon's debug bundle
collects it. The UI learns the level both at startup (daemon already in debug)
and live, by piggybacking the existing SubscribeEvents stream: the daemon
publishes a marked log-level-changed SystemEvent (and a per-subscription
snapshot), which DaemonFeed routes to guilog.DebugLog instead of an OS toast.
The UI registers its log path via a new RegisterUILog RPC so the root daemon,
which can't resolve the user's config dir, knows where to find the file.

Manual --log-file (any value) disables the daemon-driven file logging.

Fix: client/ui SetLogLevel looked up proto.LogLevel_value with the lowercase
logrus name, which never matched the uppercase enum keys and silently fell back
to INFO — so trace/debug requests from the bundle flow had no effect.

client/server/debug.go

@@ -67,6 +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,
@@ -127,9 +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()

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
+}

client/server/server.go

@@ -67,6 +67,12 @@ type Server struct {
 
 	logFile string
 
+	// uiLogPath is the desktop UI's absolute log path, reported via
+	// RegisterUILog. Guarded by mutex. Consumed by DebugBundle so the bundle
+	// can collect the GUI log even though the daemon runs as root and can't
+	// resolve the user's config dir. Last-writer-wins (one UI per socket).
+	uiLogPath string
+
 	oauthAuthFlow oauthAuthFlow
 	// extendAuthSessionFlow holds the pending PKCE flow created by
 	// RequestExtendAuthSession until WaitExtendAuthSession resolves it.
@@ -1916,8 +1922,8 @@ func (s *Server) RemoveProfile(ctx context.Context, msg *proto.RemoveProfileRequ
 // a marked INFO/SYSTEM event over SubscribeEvents: the UI's dispatchSystemEvent
 // recognises the metadata "kind" marker and translates it into its internal
 // profile-changed signal that both the tray menu and the React profile views
-// already subscribe to (see client/ui/services/daemon_feed.go,
-// MetadataKindProfileListChanged). userMessage is intentionally empty so this
+// already subscribe to (see proto.MetadataKindProfileListChanged, recognised in
+// client/ui/services/daemon_feed.go). userMessage is intentionally empty so this
 // stays a silent refresh signal rather than a user-facing notification.
 func (s *Server) publishProfileListChanged(profileName string) {
 	s.statusRecorder.PublishEvent(
@@ -1925,7 +1931,26 @@ func (s *Server) publishProfileListChanged(profileName string) {
 		proto.SystemEvent_SYSTEM,
 		"Profile list changed",
 		"",
-		map[string]string{"kind": "profile-list-changed", "profile": profileName},
+		map[string]string{proto.MetadataKindKey: proto.MetadataKindProfileListChanged, proto.MetadataProfileKey: profileName},
+	)
+}
+
+// publishLogLevelChanged signals the desktop UI that the daemon log level
+// changed, so it can attach/detach its rotated gui-client.log. Like
+// publishProfileListChanged, this rides the SubscribeEvents stream as a marked
+// INFO/SYSTEM event (kind "log-level-changed", level the lowercase logrus
+// name); the UI's dispatchSystemEvent recognises the marker and routes it to
+// the logging toggle instead of an OS toast (userMessage is empty so it stays
+// a silent control signal). The "level" value matches log.Level.String()
+// (e.g. "debug", "info") so the UI can parse it directly. See
+// proto.MetadataKindLogLevelChanged, recognised in client/ui/services/daemon_feed.go.
+func (s *Server) publishLogLevelChanged(level string) {
+	s.statusRecorder.PublishEvent(
+		proto.SystemEvent_INFO,
+		proto.SystemEvent_SYSTEM,
+		"Log level changed",
+		"",
+		map[string]string{proto.MetadataKindKey: proto.MetadataKindLogLevelChanged, proto.MetadataLevelKey: level},
 	)
 }