feat: enhance backup process with lease management and attachment deletion

- Implemented a backup runner lease mechanism to prevent concurrent backup executions.
- Added `deleteAllAttachmentsForCiphers` function to delete attachments for multiple ciphers efficiently.
- Introduced `bulkDeleteAttachmentsByIds` method in storage to handle batch deletion of attachments.
- Updated backup execution logic to utilize the new lease management and ensure timely updates during the backup process.
- Refactored cipher deletion to handle attachments more effectively.
- Improved website icon loading with a dedicated caching mechanism for better performance.
- Added new index on `ciphers` table for `folder_id` to optimize queries related to folder management.
- Enhanced response handling for CORS policy to allow credentials for specific origins.

src/router-public.ts

@@ -61,7 +61,7 @@ function handleNwFavicon(): Response {
     status: 200,
     headers: {
       'Content-Type': 'image/svg+xml; charset=utf-8',
-      'Cache-Control': `public, max-age=${LIMITS.cache.iconTtlSeconds}`,
+      'Cache-Control': `public, max-age=${LIMITS.cache.iconTtlSeconds}, immutable`,
     },
   });
 }
@@ -181,7 +181,7 @@ async function handleWebsiteIcon(host: string, fallbackMode: 'default' | 'not-fo
         status: 200,
         headers: {
           'Content-Type': resp.headers.get('Content-Type') || 'image/png',
-          'Cache-Control': `public, max-age=${LIMITS.cache.iconTtlSeconds}`,
+          'Cache-Control': `public, max-age=${LIMITS.cache.iconTtlSeconds}, immutable`,
         },
       });
     }