feat: improve VIN camera crop overlay-to-crop alignment and touch targets (refs #123)

Bridge guidance overlay position to crop tool initial coordinates so the
crop box appears centered matching the viewfinder guide. Increase handle
touch targets to 44px (32px on compact viewports) for mobile usability.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/shared/components/CameraCapture/CameraCapture.tsx

@@ -12,6 +12,7 @@ import {
   DEFAULT_ACCEPTED_FORMATS,
   DEFAULT_MAX_FILE_SIZE,
   GUIDANCE_CONFIGS,
+  getInitialCropForGuidance,
 } from './types';
 import { useCameraPermission } from './useCameraPermission';
 import { CameraViewfinder } from './CameraViewfinder';
@@ -192,6 +193,9 @@ export const CameraCapture: React.FC<CameraCaptureProps> = ({
   const cropAspectRatio =
     guidanceType !== 'none' ? GUIDANCE_CONFIGS[guidanceType].aspectRatio : undefined;
 
+  // Calculate crop coordinates centered on the guidance overlay area
+  const cropInitialArea = getInitialCropForGuidance(guidanceType);
+
   // Render permission error state
   if (permissionState === 'denied' && !useFallback) {
     return (
@@ -245,6 +249,7 @@ export const CameraCapture: React.FC<CameraCaptureProps> = ({
     return (
       <CropTool
         imageSrc={capturedImageSrc}
+        initialCrop={cropInitialArea}
         lockAspectRatio={guidanceType !== 'none' && guidanceType !== 'vin'}
         aspectRatio={cropAspectRatio}
         onConfirm={handleCropConfirm}