docs(webrtc_controller_flutter): 更新项目文档以反映重构后的架构

AGENTS.md 与 README.md 同步更新：根据实际代码结构重写目录树、技术栈、架构分层及编码规范，移除旧版内联示例并补充新的开发约定与代码生成命令。

webrtc_controller_flutter/lib/features/auth/presentation/auth_controller.dart

@@ -0,0 +1,56 @@
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+import '../data/auth_providers.dart';
+import '../domain/auth_repository.dart';
+import '../domain/auth_state.dart';
+
+part 'auth_controller.g.dart';
+
+/// 登录状态控制器。
+@Riverpod(keepAlive: true)
+class AuthController extends _$AuthController {
+  AuthRepository get _repository => ref.read(authRepositoryProvider);
+
+  @override
+  FutureOr<AuthState> build() async {
+    final repository = ref.watch(authRepositoryProvider);
+    await repository.restore();
+    final loggedIn =
+        repository.accessToken != null && await repository.hasRefreshToken();
+    return AuthState(
+      loggedIn: loggedIn,
+      restoring: false,
+      username: await repository.getUsername(),
+    );
+  }
+
+  /// 登录：成功返回 true，失败返回 false 并写入错误信息。
+  Future<bool> login(String username, String password) async {
+    try {
+      await _repository.login(username, password);
+      state = AsyncData(
+        AuthState(loggedIn: true, username: username),
+      );
+      return true;
+    } catch (e) {
+      state = AsyncData(
+        AuthState(loggedIn: false, error: e.toString()),
+      );
+      return false;
+    }
+  }
+
+  /// 退出登录：清空令牌并复位状态。
+  Future<void> logout() async {
+    await _repository.clear();
+    state = const AsyncData(AuthState());
+  }
+
+  /// 清空错误信息。
+  void clearError() {
+    final current = state.valueOrNull;
+    if (current != null && current.error != null) {
+      state = AsyncData(current.copyWith(error: null));
+    }
+  }
+}