fix(admin): return contact_email from the revoke query (#260)

The revoke route's RETURNING clause omitted contact_email while its result was typed as UploadLinkRow, which declares the field as present. No user-visible effect since the response was never checked for it, but the type asserted something the query did not actually return. Added the column so the two agree.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/src/routes/adminUploadLinks.ts

@@ -182,7 +182,7 @@ router.post('/:id/revoke', asyncRoute(async (req: Request, res: Response) => {
   const { rows } = await pool.query<UploadLinkRow>(
     `UPDATE upload_links SET revoked_at = COALESCE(revoked_at, now())
      WHERE id = $1
-     RETURNING id, label, revoked_at, submission_count, max_submissions, last_used_at, created_at`,
+     RETURNING id, label, contact_email, revoked_at, submission_count, max_submissions, last_used_at, created_at`,
     [req.params.id]
   );