feat(scanner-ui): show community verification status in found-car sheet

- Include confirmation_count in global_cars lookup
- Display verification state and confirmation count in found catalog bottom sheet
- Improve trust/feedback loop for collaborative validation workflow

lib/screens/scan_tab.dart

@@ -318,7 +318,7 @@ class ScanTabState extends State<ScanTab> {
 
       final globalCar = await supabase
           .from('global_cars')
-          .select('hw_id, name, series, year, color, is_verified')
+          .select('hw_id, name, series, year, color, is_verified, confirmation_count')
           .eq('hw_id', hwId)
           .maybeSingle();
 
@@ -443,6 +443,7 @@ class _FoundCarSheet extends StatelessWidget {
     final series = car['series'] as String?;
     final year = car['year'];
     final verified = car['is_verified'] == true;
+    final confirmations = (car['confirmation_count'] as num?)?.toInt() ?? 0;
 
     return Padding(
       padding: EdgeInsets.only(
@@ -479,6 +480,14 @@ class _FoundCarSheet extends StatelessWidget {
               fontSize: 12,
             ),
           ),
+          const SizedBox(height: 4),
+          Text(
+            '$confirmations confirmation${confirmations == 1 ? '' : 's'}',
+            style: const TextStyle(
+              color: AppColors.textHint,
+              fontSize: 12,
+            ),
+          ),
           const SizedBox(height: 16),
           SizedBox(
             width: double.infinity,