feat: 蓝牙血压计基础架构 + UI配色体系升级

- 新增 AppColors 配色体系（紫蓝渐变 + 超大圆角 + 漂浮卡片）
- 新增 OmronBleService（BLE 扫描/连接/SFLOAT 协议解析）
- 新增 BpReading 数据模型 + 血压数据自动同步后端
- 新增 DeviceScanPage（血压计扫描绑定页）+ DeviceBindPage（已绑定管理页）
- 侧边栏新增"蓝牙设备"入口，ProfilePage 移除设备管理
- Android/iOS BLE 权限配置（BLUETOOTH_SCAN/CONNECT）
- AppTheme 升级：新阴影系统、新语义色、圆角放大

health_app/lib/providers/omron_device_provider.dart

@@ -0,0 +1,92 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'auth_provider.dart';
+import 'data_providers.dart';
+import '../models/bp_reading.dart';
+import '../services/omron_ble_service.dart';
+
+/// BLE 服务单例
+final omronBleServiceProvider = Provider<OmronBleService>((ref) {
+  return OmronBleService();
+});
+
+/// 设备绑定状态
+class DeviceBindState {
+  final bool isBound;
+  final String? mac;
+  final String? name;
+  final String? lastSync;
+  final bool isConnected;
+  final BpReading? lastReading;
+
+  const DeviceBindState({
+    this.isBound = false,
+    this.mac,
+    this.name,
+    this.lastSync,
+    this.isConnected = false,
+    this.lastReading,
+  });
+
+  DeviceBindState copyWith({
+    bool? isBound,
+    String? mac,
+    String? name,
+    String? lastSync,
+    bool? isConnected,
+    BpReading? lastReading,
+  }) => DeviceBindState(
+    isBound: isBound ?? this.isBound,
+    mac: mac ?? this.mac,
+    name: name ?? this.name,
+    lastSync: lastSync ?? this.lastSync,
+    isConnected: isConnected ?? this.isConnected,
+    lastReading: lastReading ?? this.lastReading,
+  );
+}
+
+class DeviceBindNotifier extends Notifier<DeviceBindState> {
+  @override
+  DeviceBindState build() {
+    _loadBinding();
+    return const DeviceBindState();
+  }
+
+  Future<void> _loadBinding() async {
+    final db = ref.read(localDbProvider);
+    final mac = await db.read('bp_device_mac');
+    final name = await db.read('bp_device_name');
+    final lastSync = await db.read('bp_last_sync');
+    if (mac != null && mac.isNotEmpty) {
+      state = state.copyWith(isBound: true, mac: mac, name: name, lastSync: lastSync);
+    }
+  }
+
+  Future<void> bind(String mac, String name) async {
+    final db = ref.read(localDbProvider);
+    await db.write('bp_device_mac', mac);
+    await db.write('bp_device_name', name);
+    state = state.copyWith(isBound: true, mac: mac, name: name);
+  }
+
+  Future<void> unbind() async {
+    final db = ref.read(localDbProvider);
+    await db.delete('bp_device_mac');
+    await db.delete('bp_device_name');
+    await db.delete('bp_last_sync');
+    state = const DeviceBindState();
+  }
+
+  void setConnected(bool connected) {
+    state = state.copyWith(isConnected: connected);
+  }
+
+  Future<void> onReading(BpReading reading) async {
+    final db = ref.read(localDbProvider);
+    final lastSync = '${reading.timestamp.month}/${reading.timestamp.day} ${reading.timestamp.hour}:${reading.timestamp.minute.toString().padLeft(2, '0')}';
+    await db.write('bp_last_sync', lastSync);
+    state = state.copyWith(lastSync: lastSync, lastReading: reading);
+    ref.invalidate(latestHealthProvider);
+  }
+}
+
+final omronDeviceProvider = NotifierProvider<DeviceBindNotifier, DeviceBindState>(DeviceBindNotifier.new);