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/model/model_recording_session.dart

@@ -11,6 +11,9 @@ class RecordingSessionState {
     this.isBatteryOptimizedIgnored = true,
     this.notificationsGranted = true,
     this.isMicrophoneGranted = false,
+    this.zoomRatio = 1.0,
+    this.minZoomRatio = 1.0,
+    this.maxZoomRatio = 3.0,
     this.lastOutputPath,
     this.lastSavedDisplayName,
     this.errorMessage,
@@ -26,6 +29,9 @@ class RecordingSessionState {
   final bool isBatteryOptimizedIgnored;
   final bool notificationsGranted;
   final bool isMicrophoneGranted;
+  final double zoomRatio;
+  final double minZoomRatio;
+  final double maxZoomRatio;
   final String? lastOutputPath;
   final String? lastSavedDisplayName;
   final String? errorMessage;
@@ -51,6 +57,9 @@ class RecordingSessionState {
     bool? isBatteryOptimizedIgnored,
     bool? notificationsGranted,
     bool? isMicrophoneGranted,
+    double? zoomRatio,
+    double? minZoomRatio,
+    double? maxZoomRatio,
     String? lastOutputPath,
     String? lastSavedDisplayName,
     String? errorMessage,
@@ -69,6 +78,9 @@ class RecordingSessionState {
           isBatteryOptimizedIgnored ?? this.isBatteryOptimizedIgnored,
       notificationsGranted: notificationsGranted ?? this.notificationsGranted,
       isMicrophoneGranted: isMicrophoneGranted ?? this.isMicrophoneGranted,
+      zoomRatio: zoomRatio ?? this.zoomRatio,
+      minZoomRatio: minZoomRatio ?? this.minZoomRatio,
+      maxZoomRatio: maxZoomRatio ?? this.maxZoomRatio,
       lastOutputPath: lastOutputPath ?? this.lastOutputPath,
       lastSavedDisplayName: clearLastSaved
           ? null