Fix admin AI nav bug, add rescan feature

- Fix Blade parse error in admin AI settings (Blade was interpreting
  JSON braces in DEFAULT_PROMPT as template tags, breaking the navbar)
  — pass defaultPrompt from controller instead
- Add rescan: POST /nail-polishes/{id}/rescan creates a new import for
  an existing nail polish and updates its fields after AI analysis
- Add KI-Rescan button on collection cards (only if image exists)

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

resources/views/admin/ai/show.blade.php

@@ -93,8 +93,9 @@
 
 @section('scripts')
 <script>
+const defaultPrompt = @json($defaultPrompt);
 function resetPrompt() {
-    document.getElementById('prompt').value = @json(\App\Models\AiSetting::DEFAULT_PROMPT);
+    document.getElementById('prompt').value = defaultPrompt;
 }
 </script>
 @endsection