fix(s3): replace DeleteObjectsCommand with per-key deletes for CF Workers compat

DeleteObjectsCommand returns XML that requires DOMParser to parse, but
Cloudflare Workers doesn't have DOMParser. Use parallel deleteObject calls instead.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/services/s3.test.ts

@@ -204,17 +204,11 @@ describe('S3Service', () => {
   })
 
   describe('deleteObjects', () => {
-    it('sends DeleteObjectsCommand with keys', async () => {
-      mockSend.mockResolvedValueOnce({ $metadata: {} })
+    it('sends individual DeleteObjectCommand for each key', async () => {
+      mockSend.mockResolvedValue({ $metadata: {} })
       await service.deleteObjects(storage, ['a.jpg', 'b.jpg'])
-      expect(mockSend).toHaveBeenCalledWith(
-        expect.objectContaining({
-          input: {
-            Bucket: 'my-bucket',
-            Delete: { Objects: [{ Key: 'a.jpg' }, { Key: 'b.jpg' }] },
-          },
-        }),
-      )
+      expect(mockSend).toHaveBeenCalledWith(expect.objectContaining({ input: { Bucket: 'my-bucket', Key: 'a.jpg' } }))
+      expect(mockSend).toHaveBeenCalledWith(expect.objectContaining({ input: { Bucket: 'my-bucket', Key: 'b.jpg' } }))
     })
 
     it('skips API call for empty keys array', async () => {

server/services/s3.ts

@@ -1,7 +1,6 @@
 import {
   CopyObjectCommand,
   DeleteObjectCommand,
-  DeleteObjectsCommand,
   GetObjectCommand,
   HeadObjectCommand,
   PutObjectCommand,
@@ -89,12 +88,8 @@ export class S3Service {
 
   async deleteObjects(storage: Storage, keys: string[]): Promise<void> {
     if (keys.length === 0) return
-    const client = this.createClient(storage)
-    await client.send(
-      new DeleteObjectsCommand({
-        Bucket: storage.bucket,
-        Delete: { Objects: keys.map((Key) => ({ Key })) },
-      }),
-    )
+    // DeleteObjectsCommand returns XML which requires DOMParser to parse.
+    // Cloudflare Workers doesn't have DOMParser, so we delete one-by-one.
+    await Promise.all(keys.map((key) => this.deleteObject(storage, key)))
   }
 }