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

static/js/recipes.js

@@ -1,6 +1,7 @@
 // Recipe manager module
 import { appCore } from './core.js';
 import { ImportManager } from './managers/ImportManager.js';
+import { BatchImportManager } from './managers/BatchImportManager.js';
 import { RecipeModal } from './components/RecipeModal.js';
 import { state, getCurrentPageState } from './state/index.js';
 import { getSessionItem, removeSessionItem } from './utils/storageHelpers.js';
@@ -46,6 +47,10 @@ class RecipeManager {
         // Initialize ImportManager
         this.importManager = new ImportManager();
 
+        // Initialize BatchImportManager and make it globally accessible
+        this.batchImportManager = new BatchImportManager();
+        window.batchImportManager = this.batchImportManager;
+
         // Initialize RecipeModal
         this.recipeModal = new RecipeModal();