refactor(screenshot): extract macOS crop-target decision to keep classifier under the complexity budget

classifyAppleCropTarget inlined the macOS surface decision, pushing its
cyclomatic complexity to the fallow threshold. Move it back out to a
small helper so the target classifier stays within budget.

Author: thymikee

src/daemon/screenshot-crop-target.ts

@@ -88,7 +88,7 @@ function classifyAppleCropTarget(
     case 'tvos':
       return 'tvos';
     case 'macos':
-      return surface === 'app' || surface === 'frontmost-app' ? 'macos-app-window' : 'macos-helper';
+      return classifyMacOsCropTarget(surface);
     case 'watchos':
     case 'visionos':
       // Stored records carry the reserved OSes although discovery never populates them; a
@@ -98,6 +98,10 @@ function classifyAppleCropTarget(
   }
 }
 
+function classifyMacOsCropTarget(surface: SessionSurface | undefined): CropTarget {
+  return surface === 'app' || surface === 'frontmost-app' ? 'macos-app-window' : 'macos-helper';
+}
+
 function cropRefusal(target: string, rejectionReason?: ScreenshotCropReason): AppError {
   return new AppError(
     'UNSUPPORTED_OPERATION',