Fix camera position switch using runtime CameraManager.setCameraPosition()

- Add onChange handler in CustomCameraScreen to watch cameraPositionRaw
- Call cameraManager.setCameraPosition() at runtime when setting changes
- Camera now switches without needing to recreate the entire MCamera view
- Keep onDismiss fallback in ContentView as safety net

SelfieCam/Features/Camera/Views/CustomCameraScreen.swift

@@ -39,6 +39,9 @@ struct CustomCameraScreen: MCameraScreen {
     @GestureState private var magnification: CGFloat = 1.0
     @State private var lastMagnification: CGFloat = 1.0
     
+    // Track camera position for runtime switching
+    @State private var currentCameraPosition: CameraPosition?
+
     var body: some View {
         ZStack {
             // Camera preview with pinch gesture - Metal layer doesn't respect SwiftUI clipping
@@ -159,6 +162,24 @@ struct CustomCameraScreen: MCameraScreen {
             updateFlashSyncState()
             // Initialize zoom gesture state
             lastMagnification = zoomFactor
+            // Track initial camera position
+            currentCameraPosition = cameraSettings.cameraPosition
+        }
+        .onChange(of: cameraSettings.cameraPositionRaw) { _, newRaw in
+            // Switch camera when position changes in settings
+            let newPosition: CameraPosition = newRaw == "front" ? .front : .back
+            if currentCameraPosition != newPosition {
+                Design.debugLog("Camera position changed to \(newPosition) - switching camera...")
+                currentCameraPosition = newPosition
+                Task {
+                    do {
+                        try await cameraManager.setCameraPosition(newPosition)
+                        Design.debugLog("Camera switched successfully to \(newPosition)")
+                    } catch {
+                        Design.debugLog("Failed to switch camera: \(error)")
+                    }
+                }
+            }
         }
         .onChange(of: cameraSettings.isFlashSyncedWithRingLight) { _, _ in
             // Only update when sync setting changes, not on every color change