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

resources/views/user-nail-polishes/index.blade.php

@@ -65,7 +65,15 @@
                                 <span class="np-brand">{{ $nailPolish->manufacturer->name }}</span>
                             @endif
                         </div>
-                        <div class="mt-3">
+                        <div class="mt-3 d-flex flex-column gap-2">
+                            @if($nailPolish->image_path)
+                                <form method="POST" action="{{ route('nail-polishes.rescan', $nailPolish) }}">
+                                    @csrf
+                                    <button type="submit" class="btn btn-outline-secondary btn-sm w-100">
+                                        <i class="fas fa-sync-alt me-1"></i>KI-Rescan
+                                    </button>
+                                </form>
+                            @endif
                             <form method="POST" action="{{ route('user-nail-polishes.remove', $nailPolish) }}"
                                   onsubmit="return confirm('Lack aus der Sammlung entfernen?')">
                                 @csrf