feat: implement batch import recipe functionality (frontend + backend fixes)

Backend fixes:
- Add missing API route for /api/lm/recipes/batch-import/progress (GET)
- Add missing API route for /api/lm/recipes/batch-import/directory (POST)
- Add missing API route for /api/lm/recipes/browse-directory (POST)
- Register WebSocket endpoint for batch import progress
- Fix skip_no_metadata default value (True -> False) to allow no-LoRA imports
- Add items array to BatchImportProgress.to_dict() for detailed results

Frontend implementation:
- Create BatchImportManager.js with complete batch import workflow
- Add directory browser UI for selecting folders
- Add batch import modal with URL list and directory input modes
- Implement real-time progress tracking (WebSocket + HTTP polling)
- Add results summary with success/failed/skipped statistics
- Add expandable details view showing individual item status
- Auto-refresh recipe list after import completion

UI improvements:
- Add spinner animation for importing status
- Simplify results summary UI to match progress stats styling
- Fix current item text alignment
- Fix dark theme styling for directory browser button
- Fix batch import button styling consistency

Translations:
- Add batch import related i18n keys to all locale files
- Run sync_translation_keys.py to sync all translations

Fixes:
- Batch import now allows images without LoRAs (matches single import behavior)
- Progress endpoint now returns complete items array with status details
- Results view correctly displays skipped items with error messages

templates/recipes.html

@@ -7,10 +7,12 @@
 <link rel="stylesheet" href="/loras_static/css/components/card.css?v={{ version }}">
 <link rel="stylesheet" href="/loras_static/css/components/recipe-modal.css?v={{ version }}">
 <link rel="stylesheet" href="/loras_static/css/components/import-modal.css?v={{ version }}">
+<link rel="stylesheet" href="/loras_static/css/components/batch-import-modal.css?v={{ version }}">
 {% endblock %}
 
 {% block additional_components %}
 {% include 'components/import_modal.html' %}
+{% include 'components/batch_import_modal.html' %}
 {% include 'components/recipe_modal.html' %}
 
 <div id="recipeContextMenu" class="context-menu" style="display: none;">
@@ -85,6 +87,10 @@
                 <button onclick="importManager.showImportModal()"><i class="fas fa-file-import"></i> {{
                     t('recipes.controls.import.action') }}</button>
             </div>
+            <div title="{{ t('recipes.batchImport.title') }}" class="control-group">
+                <button onclick="batchImportManager.showModal()"><i class="fas fa-layer-group"></i> {{
+                    t('recipes.batchImport.action') }}</button>
+            </div>
             <div class="control-group" title="{{ t('loras.controls.bulk.title') }}">
                 <button id="bulkOperationsBtn" data-action="bulk" title="{{ t('loras.controls.bulk.title') }}">
                     <i class="fas fa-th-large"></i> <span><span>{{ t('loras.controls.bulk.action') }}</span>