实现缩放功能：增加缩放功能检索和设置方法，更新UI以支持缩放调整，增强缩放比例的状态管理。

lib/features/recording/view-model/view_model_recording.dart

@@ -193,6 +193,7 @@ class RecordingViewModel extends Notifier<RecordingModel> {
     await _listenStatus();
     try {
       final status = await _initializePreviewWithRetry();
+      await _refreshZoomCapabilities();
       _updateSession(
         (s) => s.copyWith(
           status: status,
@@ -239,6 +240,7 @@ class RecordingViewModel extends Notifier<RecordingModel> {
     );
     try {
       final status = await _initializePreviewWithRetry();
+      await _refreshZoomCapabilities();
       _updateSession(
         (s) => s.copyWith(
           status: status,
@@ -309,6 +311,47 @@ class RecordingViewModel extends Notifier<RecordingModel> {
     return status?.isGranted == true || status?.isLimited == true;
   }
 
+  /// 读取相机支持的倍距范围并同步当前倍距。
+  Future<void> _refreshZoomCapabilities() async {
+    try {
+      final zoom = await RecordingPlatform.getZoomCapabilities();
+      _updateSession(
+        (s) => s.copyWith(
+          zoomRatio: zoom.zoomRatio,
+          minZoomRatio: zoom.minZoomRatio,
+          maxZoomRatio: zoom.maxZoomRatio,
+          errorMessage: null,
+        ),
+      );
+    } on PlatformException catch (error) {
+      AppLogger.debug('读取相机倍距能力失败', error: error);
+    }
+  }
+
+  /// 设置相机倍距，原生层会返回设备实际应用后的倍距范围与当前值。
+  Future<void> setZoomRatio(double ratio) async {
+    final session = state.session;
+    final clamped = ratio
+        .clamp(session.minZoomRatio, session.maxZoomRatio)
+        .toDouble();
+
+    try {
+      final zoom = await RecordingPlatform.setZoomRatio(clamped);
+      _updateSession(
+        (s) => s.copyWith(
+          zoomRatio: zoom.zoomRatio,
+          minZoomRatio: zoom.minZoomRatio,
+          maxZoomRatio: zoom.maxZoomRatio,
+          errorMessage: null,
+        ),
+      );
+    } on PlatformException catch (error) {
+      _updateSession(
+        (s) => s.copyWith(errorMessage: error.message ?? '相机倍距设置失败'),
+      );
+    }
+  }
+
   /// 开始录制，可选开启勿扰模式。
   Future<void> startRecording({bool enableDoNotDisturb = true}) async {
     final session = state.session;