chore: release v1.0.29

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/lib/core/platform/single_instance.dart

@@ -0,0 +1,27 @@
+import 'dart:io';
+
+import 'package:flutter/foundation.dart';
+import 'package:path_provider/path_provider.dart';
+
+// Keep the RAF open so the OS lock stays alive for the lifetime of the process.
+// ignore: unused_element
+RandomAccessFile? _raf;
+
+/// Returns true if this process successfully acquired the single-instance lock.
+/// Returns false if another instance is already running.
+/// On Web / mobile / Linux the function always returns true (no restriction).
+Future<bool> acquire() async {
+  if (kIsWeb) return true;
+  if (!Platform.isWindows && !Platform.isMacOS) return true;
+
+  try {
+    final dir = await getApplicationSupportDirectory();
+    final lockFile = File('${dir.path}/jiu.lock');
+    final raf = await lockFile.open(mode: FileMode.write);
+    await raf.lock(FileLock.exclusive);
+    _raf = raf;
+    return true;
+  } catch (_) {
+    return false;
+  }
+}