Unify session-aware CLI parsing and add session-id compatibility

internal/app/session_args.go

@@ -41,3 +41,21 @@ func applyParsedSessionIDArg(command string, fs *flag.FlagSet, sessionID *string
 		return fmt.Errorf("%s: unexpected positional arguments", command)
 	}
 }
+
+func resolveParsedSessionID(command, positionalSessionID string, fs *flag.FlagSet, sessionID *string) error {
+	if strings.TrimSpace(positionalSessionID) == "" {
+		return applyParsedSessionIDArg(command, fs, sessionID)
+	}
+	if fs.NArg() != 0 {
+		return fmt.Errorf("%s: unexpected positional arguments", command)
+	}
+	return applyPositionalSessionID(command, positionalSessionID, sessionID)
+}
+
+func parseSessionAwareFlags(command string, fs *flag.FlagSet, args []string, sessionID *string) error {
+	positionalSessionID, args := pullLeadingSessionID(args)
+	if err := fs.Parse(args); err != nil {
+		return fmt.Errorf("%s: invalid flags: %w", command, err)
+	}
+	return resolveParsedSessionID(command, positionalSessionID, fs, sessionID)
+}