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/internal/debug/debug.go

@@ -229,9 +229,16 @@ scutil_dns.txt (macOS only):
 
 const (
 	clientLogFile = "client.log"
+	uiLogFile     = "gui-client.log"
 	errorLogFile  = "netbird.err"
 	stdoutLogFile = "netbird.out"
 
+	// Rotated-log glob prefixes (base log name without extension) passed to
+	// addRotatedLogFiles. The daemon's own log and the GUI log live in the same
+	// dir, so the prefixes must be disjoint to keep their rotated siblings apart.
+	clientLogPrefix = "client"
+	uiLogPrefix     = "gui-client"
+
 	darwinErrorLogPath  = "/var/log/netbird.out.log"
 	darwinStdoutLogPath = "/var/log/netbird.err.log"
 )
@@ -249,6 +256,7 @@ type BundleGenerator struct {
 	statusRecorder *peer.Status
 	syncResponse   *mgmProto.SyncResponse
 	logPath        string
+	uiLogPath      string
 	tempDir        string
 	cpuProfile     []byte
 	capturePath    string
@@ -275,6 +283,7 @@ type GeneratorDependencies struct {
 	StatusRecorder *peer.Status
 	SyncResponse   *mgmProto.SyncResponse
 	LogPath        string
+	UILogPath      string // Absolute path to the desktop UI's gui-client.log, reported via RegisterUILog. Empty if no UI registered one.
 	TempDir        string // Directory for temporary bundle zip files. If empty, os.TempDir() is used.
 	CPUProfile     []byte
 	CapturePath    string
@@ -298,6 +307,7 @@ func NewBundleGenerator(deps GeneratorDependencies, cfg BundleConfig) *BundleGen
 		statusRecorder: deps.StatusRecorder,
 		syncResponse:   deps.SyncResponse,
 		logPath:        deps.LogPath,
+		uiLogPath:      deps.UILogPath,
 		tempDir:        deps.TempDir,
 		cpuProfile:     deps.CPUProfile,
 		capturePath:    deps.CapturePath,
@@ -408,6 +418,10 @@ func (g *BundleGenerator) createArchive() error {
 		log.Errorf("failed to add logs to debug bundle: %v", err)
 	}
 
+	if err := g.addUILog(); err != nil {
+		log.Errorf("failed to add UI log to debug bundle: %v", err)
+	}
+
 	if err := g.addUpdateLogs(); err != nil {
 		log.Errorf("failed to add updater logs: %v", err)
 	}
@@ -972,7 +986,7 @@ func (g *BundleGenerator) addLogfile() error {
 		return fmt.Errorf("add client log file to zip: %w", err)
 	}
 
-	g.addRotatedLogFiles(logDir)
+	g.addRotatedLogFiles(logDir, clientLogPrefix)
 
 	stdErrLogPath := filepath.Join(logDir, errorLogFile)
 	stdoutLogPath := filepath.Join(logDir, stdoutLogFile)
@@ -992,6 +1006,25 @@ func (g *BundleGenerator) addLogfile() error {
 	return nil
 }
 
+// addUILog adds the desktop UI's gui-client.log (and its rotated siblings) to
+// the bundle. The path is reported by the UI via RegisterUILog; empty when no
+// UI registered one (e.g. headless / server). Missing file is non-fatal — the
+// UI only writes it while the daemon is in debug, so it's often absent.
+func (g *BundleGenerator) addUILog() error {
+	if g.uiLogPath == "" {
+		log.Debugf("no UI log path registered, skipping in debug bundle")
+		return nil
+	}
+
+	if err := g.addSingleLogfile(g.uiLogPath, uiLogFile); err != nil {
+		return fmt.Errorf("add UI log file to zip: %w", err)
+	}
+
+	g.addRotatedLogFiles(filepath.Dir(g.uiLogPath), uiLogPrefix)
+
+	return nil
+}
+
 // addSingleLogfile adds a single log file to the archive
 func (g *BundleGenerator) addSingleLogfile(logPath, targetName string) error {
 	logFile, err := os.Open(logPath)
@@ -1064,14 +1097,16 @@ func (g *BundleGenerator) addSingleLogFileGz(logPath, targetName string) error {
 	return nil
 }
 
-// addRotatedLogFiles adds rotated log files to the bundle based on logFileCount
-func (g *BundleGenerator) addRotatedLogFiles(logDir string) {
+// addRotatedLogFiles adds rotated log files to the bundle based on logFileCount.
+// prefix is the base log name without extension (e.g. "client", "gui-client");
+// the glob matches both files rotated by us and by logrotate on linux.
+func (g *BundleGenerator) addRotatedLogFiles(logDir, prefix string) {
 	if g.logFileCount == 0 {
 		return
 	}
 
-	// This regex will match both logs rotated by us and logrotate on linux
-	pattern := filepath.Join(logDir, "client*.log.*")
+	// This pattern matches both logs rotated by us and logrotate on linux
+	pattern := filepath.Join(logDir, prefix+"*.log.*")
 	files, err := filepath.Glob(pattern)
 	if err != nil {
 		log.Warnf("failed to glob rotated logs: %v", err)

client/internal/debug/debug_logfiles_test.go

@@ -40,6 +40,25 @@ func TestAddRotatedLogFiles_PicksUpAllVariants(t *testing.T) {
 	require.NotContains(t, names, "other.log", "unrelated files should not be in bundle")
 }
 
+// TestAddRotatedLogFiles_GUIPrefix asserts the prefix parameter scopes the glob
+// to the GUI log: gui-client.log.* rotated siblings are picked up and the
+// daemon's own client.log.* are not (and vice versa, covered above). This is
+// the load-bearing check for the gui-client.log bundle collection — the old
+// "client*.log.*" glob would have missed gui-client rotations.
+func TestAddRotatedLogFiles_GUIPrefix(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, filepath.Join(dir, "gui-client.log.1"), "gui rotated\n")
+	writeGzFile(t, filepath.Join(dir, "gui-client.log.2.gz"), "gui rotated gz\n")
+	writeFile(t, filepath.Join(dir, "client.log.1"), "daemon rotated\n")
+
+	names := runAddRotatedLogFilesPrefix(t, dir, "gui-client", 10)
+
+	require.Contains(t, names, "gui-client.log.1", "gui-client rotated file should be in bundle")
+	require.Contains(t, names, "gui-client.log.2.gz", "gui-client gz rotated file should be in bundle")
+	require.NotContains(t, names, "client.log.1", "daemon rotated file must not match the gui-client prefix")
+}
+
 // TestAddRotatedLogFiles_RespectsLogFileCount asserts that only the newest
 // logFileCount rotated files are bundled, ordered by mtime.
 func TestAddRotatedLogFiles_RespectsLogFileCount(t *testing.T) {
@@ -67,6 +86,10 @@ func TestAddRotatedLogFiles_RespectsLogFileCount(t *testing.T) {
 // runAddRotatedLogFiles calls addRotatedLogFiles against a fresh in-memory
 // zip writer and returns the set of entry names that ended up in the archive.
 func runAddRotatedLogFiles(t *testing.T, dir string, logFileCount uint32) map[string]struct{} {
+	return runAddRotatedLogFilesPrefix(t, dir, "client", logFileCount)
+}
+
+func runAddRotatedLogFilesPrefix(t *testing.T, dir, prefix string, logFileCount uint32) map[string]struct{} {
 	t.Helper()
 
 	var buf bytes.Buffer
@@ -74,7 +97,7 @@ func runAddRotatedLogFiles(t *testing.T, dir string, logFileCount uint32) map[st
 		archive:      zip.NewWriter(&buf),
 		logFileCount: logFileCount,
 	}
-	g.addRotatedLogFiles(dir)
+	g.addRotatedLogFiles(dir, prefix)
 	require.NoError(t, g.archive.Close())
 
 	zr, err := zip.NewReader(bytes.NewReader(buf.Bytes()), int64(buf.Len()))