```

feat(iOS): 更新MNN后端模型配置优化性能

将MNN主模型从Qwen3.5-4B(~2.64GiB)降级为Qwen3.5-2B(~1.1GiB)，因为4B版本
实测运行过慢，影响用户体验。iPhone17+/SME2设备使用2B模型，保留MLX
兜底方案用于模拟器和备用场景，确保AI推理性能和存储效率的平衡。
```

康康/Features/Me/ModelManagementView.swift

@@ -10,8 +10,6 @@ struct ModelManagementView: View {
     @State private var showCellularConfirm = false
     @State private var showImporter = false
     @State private var importError: String?
-    @AppStorage(QuickRegionRecognitionEngine.storageKey)
-    private var quickRegionEngineRaw = QuickRegionRecognitionEngine.defaultValue.rawValue
 
     private let monitor = NWPathMonitor()
     private let monitorQueue = DispatchQueue(label: "kk.netmonitor")
@@ -27,8 +25,6 @@ struct ModelManagementView: View {
                     modelCard(kind)
                 }
 
-                recognitionEngineCard
-
                 actionButtons
                     .padding(.top, 4)
 
@@ -80,46 +76,6 @@ struct ModelManagementView: View {
         }
     }
 
-    // MARK: - 拍照识别引擎
-
-    private var selectedRecognitionEngine: QuickRegionRecognitionEngine {
-        QuickRegionRecognitionEngine(storedValue: quickRegionEngineRaw)
-    }
-
-    private var recognitionEngineCard: some View {
-        VStack(alignment: .leading, spacing: 12) {
-            HStack(alignment: .top, spacing: 10) {
-                ZStack {
-                    Circle().fill(Tj.Palette.sand2)
-                    Image(systemName: "camera.metering.center.weighted")
-                        .font(.tjScaled( 18))
-                        .foregroundStyle(Tj.Palette.text2)
-                }
-                .frame(width: 38, height: 38)
-
-                VStack(alignment: .leading, spacing: 3) {
-                    Text("异常项拍照识别")
-                        .font(.tjScaled( 15, weight: .semibold))
-                        .foregroundStyle(Tj.Palette.text)
-                    Text(selectedRecognitionEngine.detail)
-                        .font(.tjScaled( 12))
-                        .foregroundStyle(Tj.Palette.text3)
-                }
-                Spacer()
-            }
-
-            Picker("异常项拍照识别", selection: $quickRegionEngineRaw) {
-                ForEach(QuickRegionRecognitionEngine.allCases) { engine in
-                    Text(engine.title).tag(engine.rawValue)
-                }
-            }
-            .pickerStyle(.segmented)
-        }
-        .padding(14)
-        .frame(maxWidth: .infinity, alignment: .leading)
-        .tjCard()
-    }
-
     // MARK: - 模型卡片
 
     private func modelCard(_ kind: ModelKind) -> some View {
@@ -198,7 +154,7 @@ struct ModelManagementView: View {
         } else if allReady {
             HStack(spacing: 6) {
                 Image(systemName: "checkmark.seal.fill")
-                Text("Qwen3.5-4B 已就绪")
+                Text("Qwen3.5-2B 已就绪")
             }
             .font(.tjScaled( 13, weight: .semibold))
             .foregroundStyle(Tj.Palette.leaf)