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.

util/log.go

@@ -40,6 +40,45 @@ func InitLogger(logger *log.Logger, logLevel string, logs ...string) error {
 	if err != nil {
 		return fmt.Errorf("failed parsing log-level %s: %w", logLevel, err)
 	}
+
+	logFmt, err := buildWriters(logger, logs...)
+	if err != nil {
+		return err
+	}
+
+	switch logFmt {
+	case "json":
+		formatter.SetJSONFormatter(logger)
+	case "syslog":
+		formatter.SetSyslogFormatter(logger)
+	default:
+		formatter.SetTextFormatter(logger)
+	}
+	logger.SetLevel(level)
+
+	setGRPCLibLogger(logger)
+
+	return nil
+}
+
+// SetLogOutputs re-points an already-initialized logger to the given targets
+// (console/syslog/file), with the same target semantics as InitLogger, but
+// without re-parsing the level or resetting the formatter. The desktop GUI uses
+// it to attach the rotated gui-client.log alongside the console when the daemon
+// enters debug, and drop back to console-only when it leaves.
+func SetLogOutputs(logger *log.Logger, logs ...string) error {
+	if _, err := buildWriters(logger, logs...); err != nil {
+		return err
+	}
+	setGRPCLibLogger(logger)
+	return nil
+}
+
+// buildWriters resolves the given log targets to writers and points the logger
+// at them (single writer or MultiWriter). It returns the log format implied by
+// the targets (syslog forces "syslog"; otherwise the NB_LOG_FORMAT env value).
+// Shared by InitLogger and SetLogOutputs.
+func buildWriters(logger *log.Logger, logs ...string) (string, error) {
 	var writers []io.Writer
 	logFmt := os.Getenv("NB_LOG_FORMAT")
 
@@ -61,7 +100,7 @@ func InitLogger(logger *log.Logger, logLevel string, logs ...string) error {
 		default:
 			writer, err := setupLogFile(logPath, isRotationDisabled(logger))
 			if err != nil {
-				return fmt.Errorf("failed setting up log file: %s, %w", logPath, err)
+				return "", fmt.Errorf("failed setting up log file: %s, %w", logPath, err)
 			}
 			writers = append(writers, writer)
 		}
@@ -73,19 +112,7 @@ func InitLogger(logger *log.Logger, logLevel string, logs ...string) error {
 		logger.SetOutput(writers[0])
 	}
 
-	switch logFmt {
-	case "json":
-		formatter.SetJSONFormatter(logger)
-	case "syslog":
-		formatter.SetSyslogFormatter(logger)
-	default:
-		formatter.SetTextFormatter(logger)
-	}
-	logger.SetLevel(level)
-
-	setGRPCLibLogger(logger)
-
-	return nil
+	return logFmt, nil
 }
 
 // FindFirstLogPath returns the first logs entry that could be a log path, that is neither empty, nor a special value