feat(attachments,security): migrate attachment processing to web worker and update CORS policy

- Add web worker for PDF attachment processing to improve performance and prevent UI blocking
- Create add-attachments.worker.js with TypeScript definitions for type safety
- Implement worker message handling with success and error responses
- Update nginx.conf to use Cross-Origin-Resource-Policy instead of Cross-Origin-Embedder-Policy for better cross-origin resource sharing
- Refactor add-attachments.ts to use worker-based processing with transferable objects
- Update main.ts to add home logo click handler for navigation
- Improve error handling with worker error event listener
- Add validation checks for PDF file availability before processing attachments

nginx.conf

@@ -35,6 +35,6 @@ http {
         add_header X-Content-Type-Options "nosniff" always;
         add_header X-XSS-Protection "1; mode=block" always;
         add_header Cross-Origin-Opener-Policy "same-origin" always;
-        add_header Cross-Origin-Embedder-Policy "require-corp" always;
+        add_header Cross-Origin-Resource-Policy "cross-origin" always;
     }
 }