Enable face-driven auto focus

This uses on-device vision functions to prioritize faces (up to 10) when auto focusing. It's helpful when subjects are moving around the frame.

Author: cwbooth5

SnapSafe/Screens/Camera/Services/CameraDeviceService.swift

@@ -101,11 +101,14 @@ final class CameraDeviceService: ObservableObject, @preconcurrency CameraDeviceP
             if device.isFocusModeSupported(.continuousAutoFocus) {
                 device.focusMode = .continuousAutoFocus
                 device.isSmoothAutoFocusEnabled = true
-                
+
                 if device.isAutoFocusRangeRestrictionSupported {
                     device.autoFocusRangeRestriction = .none
                 }
             }
+
+            // Enable face-driven autofocus (prioritizes detected faces)
+            device.automaticallyAdjustsFaceDrivenAutoFocusEnabled = true
 
             if device.isExposureModeSupported(.continuousAutoExposure) {
                 device.exposureMode = .continuousAutoExposure