feat: Flutter 客户端 App + Web UI APK 下载入口

- 新增 Flutter 跨平台客户端项目 (clients/flutter/)
  - 29 个 Dart 文件: 服务层/状态管理/5个页面/BLE配网
  - BLE 蓝牙配网: 扫描设备、写入WiFi凭据、配网状态监听
  - HTTP API 客户端: 覆盖全部端点 (播放/场景/WiFi/视频/配置/文件/插件)
  - WebSocket 实时通信: 事件流 + 自动重连
  - 暗色主题 Material 3 UI, 中文界面
  - Android 配置: minSdkVersion 21, BLE/网络权限
  - PRD 产品需求文档 + 开发任务看板
- Web UI 添加 APK 下载入口 (routes.rs)
  - 下载弹窗 + 二维码 + /download/{filename} 静态文件路由
- BLE 插件增加自动重连循环 (ble/mod.rs)
- BLE 默认设备名修正为 'Showen' (config.rs)

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

clients/flutter/lib/models/api_response.dart

@@ -0,0 +1,22 @@
+class ApiResponse {
+  const ApiResponse({required this.status, required this.message});
+
+  final String status;
+  final String message;
+
+  bool get isOk => status == 'ok';
+
+  factory ApiResponse.fromJson(Map<String, dynamic> json) {
+    return ApiResponse(
+      status: json['status'] as String? ?? 'error',
+      message: json['message'] as String? ?? '',
+    );
+  }
+
+  Map<String, dynamic> toJson() {
+    return <String, dynamic>{
+      'status': status,
+      'message': message,
+    };
+  }
+}

clients/flutter/lib/models/app_event.dart

@@ -0,0 +1,24 @@
+class AppEvent {
+  const AppEvent({required this.type, required this.payload});
+
+  final String type;
+  final Map<String, dynamic> payload;
+
+  factory AppEvent.fromJson(Map<String, dynamic> json) {
+    final dynamic rawPayload = json['data'] ?? json['payload'] ?? const <String, dynamic>{};
+    return AppEvent(
+      type: json['type'] as String? ?? 'unknown',
+      payload: _normalizePayload(rawPayload),
+    );
+  }
+
+  static Map<String, dynamic> _normalizePayload(dynamic payload) {
+    if (payload is Map<String, dynamic>) {
+      return payload;
+    }
+    if (payload is Map) {
+      return Map<String, dynamic>.from(payload);
+    }
+    return <String, dynamic>{'value': payload};
+  }
+}

clients/flutter/lib/models/ble_models.dart

@@ -0,0 +1,69 @@
+import 'dart:convert';
+
+class BleDevice {
+  const BleDevice({
+    required this.name,
+    required this.id,
+    required this.rssi,
+  });
+
+  final String name;
+  final String id;
+  final int rssi;
+}
+
+class BleStatus {
+  const BleStatus({
+    required this.ok,
+    required this.action,
+    this.state,
+    this.error,
+  });
+
+  factory BleStatus.fromJson(Map<String, dynamic> json) {
+    return BleStatus(
+      ok: json['ok'] == true,
+      action: (json['action'] ?? '').toString(),
+      state: json['state']?.toString(),
+      error: json['error']?.toString(),
+    );
+  }
+
+  factory BleStatus.fromRawJson(String source) {
+    final dynamic decoded = jsonDecode(source);
+    if (decoded is! Map<String, dynamic>) {
+      throw const FormatException('BLE status payload is not a JSON object');
+    }
+    return BleStatus.fromJson(decoded);
+  }
+
+  static const BleStatus idle = BleStatus(ok: true, action: 'idle');
+
+  final bool ok;
+  final String action;
+  final String? state;
+  final String? error;
+
+  bool get isQueued => state == 'queued';
+
+  bool get isSuccess => ok && !isQueued;
+
+  String get message {
+    if ((error ?? '').isNotEmpty) {
+      return error!;
+    }
+    if ((state ?? '').isNotEmpty) {
+      return state!;
+    }
+    return action;
+  }
+}
+
+enum ProvisioningState {
+  scanning,
+  connecting,
+  writingCredentials,
+  connectingWifi,
+  success,
+  failed,
+}

clients/flutter/lib/models/ble_status.dart

@@ -0,0 +1,23 @@
+class BleServiceStatus {
+  const BleServiceStatus({
+    required this.running,
+    required this.embedded,
+    this.deviceName,
+  });
+
+  final bool running;
+  final bool embedded;
+  final String? deviceName;
+
+  factory BleServiceStatus.initial() {
+    return const BleServiceStatus(running: false, embedded: false);
+  }
+
+  factory BleServiceStatus.fromJson(Map<String, dynamic> json) {
+    return BleServiceStatus(
+      running: json['running'] as bool? ?? false,
+      embedded: json['embedded'] as bool? ?? false,
+      deviceName: json['device_name'] as String?,
+    );
+  }
+}

clients/flutter/lib/models/device_status.dart

@@ -0,0 +1,54 @@
+import 'ble_status.dart';
+import 'player_status.dart';
+import 'wifi_status.dart';
+
+class DeviceStatus {
+  const DeviceStatus({
+    required this.connected,
+    required this.connectionType,
+    this.deviceName,
+    this.ipAddress,
+    this.playerStatus,
+    this.wifiStatus,
+    this.bleStatus,
+    this.updatedAt,
+  });
+
+  final bool connected;
+  final String connectionType;
+  final String? deviceName;
+  final String? ipAddress;
+  final PlayerStatus? playerStatus;
+  final WifiStatus? wifiStatus;
+  final BleServiceStatus? bleStatus;
+  final DateTime? updatedAt;
+
+  factory DeviceStatus.initial() {
+    return const DeviceStatus(
+      connected: false,
+      connectionType: 'offline',
+    );
+  }
+
+  DeviceStatus copyWith({
+    bool? connected,
+    String? connectionType,
+    String? deviceName,
+    String? ipAddress,
+    PlayerStatus? playerStatus,
+    WifiStatus? wifiStatus,
+    BleServiceStatus? bleStatus,
+    DateTime? updatedAt,
+  }) {
+    return DeviceStatus(
+      connected: connected ?? this.connected,
+      connectionType: connectionType ?? this.connectionType,
+      deviceName: deviceName ?? this.deviceName,
+      ipAddress: ipAddress ?? this.ipAddress,
+      playerStatus: playerStatus ?? this.playerStatus,
+      wifiStatus: wifiStatus ?? this.wifiStatus,
+      bleStatus: bleStatus ?? this.bleStatus,
+      updatedAt: updatedAt ?? this.updatedAt,
+    );
+  }
+}

clients/flutter/lib/models/player_status.dart

@@ -0,0 +1,68 @@
+class PlayerStatus {
+  const PlayerStatus({
+    required this.running,
+    required this.paused,
+    required this.inTransition,
+    required this.currentIndex,
+    required this.playlistLength,
+    this.currentVideo,
+  });
+
+  final bool running;
+  final bool paused;
+  final bool inTransition;
+  final int currentIndex;
+  final int playlistLength;
+  final String? currentVideo;
+
+  factory PlayerStatus.initial() {
+    return const PlayerStatus(
+      running: false,
+      paused: false,
+      inTransition: false,
+      currentIndex: 0,
+      playlistLength: 0,
+      currentVideo: null,
+    );
+  }
+
+  factory PlayerStatus.fromJson(Map<String, dynamic> json) {
+    return PlayerStatus(
+      running: json['running'] as bool? ?? false,
+      paused: json['paused'] as bool? ?? false,
+      inTransition: json['in_transition'] as bool? ?? false,
+      currentIndex: json['current_index'] as int? ?? 0,
+      playlistLength: json['playlist_length'] as int? ?? 0,
+      currentVideo: json['current_video'] as String?,
+    );
+  }
+
+  Map<String, dynamic> toJson() {
+    return <String, dynamic>{
+      'running': running,
+      'paused': paused,
+      'in_transition': inTransition,
+      'current_index': currentIndex,
+      'playlist_length': playlistLength,
+      'current_video': currentVideo,
+    };
+  }
+
+  PlayerStatus copyWith({
+    bool? running,
+    bool? paused,
+    bool? inTransition,
+    int? currentIndex,
+    int? playlistLength,
+    String? currentVideo,
+  }) {
+    return PlayerStatus(
+      running: running ?? this.running,
+      paused: paused ?? this.paused,
+      inTransition: inTransition ?? this.inTransition,
+      currentIndex: currentIndex ?? this.currentIndex,
+      playlistLength: playlistLength ?? this.playlistLength,
+      currentVideo: currentVideo ?? this.currentVideo,
+    );
+  }
+}

clients/flutter/lib/models/video_item.dart

@@ -0,0 +1,23 @@
+class VideoItem {
+  const VideoItem({required this.name, required this.size});
+
+  final String name;
+  final int size;
+
+  factory VideoItem.fromJson(Map<String, dynamic> json) {
+    return VideoItem(
+      name: json['name'] as String? ?? '',
+      size: json['size'] as int? ?? 0,
+    );
+  }
+
+  String get sizeLabel {
+    if (size >= 1024 * 1024) {
+      return '${(size / (1024 * 1024)).toStringAsFixed(1)} MB';
+    }
+    if (size >= 1024) {
+      return '${(size / 1024).toStringAsFixed(1)} KB';
+    }
+    return '$size B';
+  }
+}

clients/flutter/lib/models/wifi_network.dart

@@ -0,0 +1,21 @@
+class WifiNetwork {
+  const WifiNetwork({
+    required this.ssid,
+    required this.signal,
+    required this.security,
+  });
+
+  final String ssid;
+  final int signal;
+  final String security;
+
+  factory WifiNetwork.fromJson(Map<String, dynamic> json) {
+    return WifiNetwork(
+      ssid: json['ssid'] as String? ?? '',
+      signal: json['signal'] as int? ?? 0,
+      security: json['security'] as String? ?? 'Unknown',
+    );
+  }
+
+  String get signalLabel => '$signal dBm';
+}

clients/flutter/lib/models/wifi_status.dart

@@ -0,0 +1,23 @@
+class WifiStatus {
+  const WifiStatus({
+    required this.connected,
+    this.ssid,
+    this.ip,
+  });
+
+  final bool connected;
+  final String? ssid;
+  final String? ip;
+
+  factory WifiStatus.disconnected() {
+    return const WifiStatus(connected: false);
+  }
+
+  factory WifiStatus.fromJson(Map<String, dynamic> json) {
+    return WifiStatus(
+      connected: json['connected'] as bool? ?? false,
+      ssid: json['ssid'] as String?,
+      ip: json['ip'] as String?,
+    );
+  }
+}