fix(ocr): round-4 review — defensive poll + drop dead tracking columns

Round 4 review (PR #910), no blockers:
- poll(): a 2xx body with no `status` now fails fast (logged) instead of being
  treated as perpetually pending until the deadline; defensive page index
  (`p.get("index", i)`) so a malformed page degrades rather than KeyError-ing.
- Document on poll() that job_id is namespaced (embeds "/") so the gateway route
  must be a path-capture param (GET /v1/ocr/batch/{job_id:path}).
- Drop the vestigial `status` + `updated_at` columns from batch_ocr_jobs: a row
  only ever exists while pending (terminal jobs are deleted) and the live status
  comes from a fresh poll, so a stored mirror was permanently "pending" /
  redundant with submitted_at. Simplifies the migration, store, and dataclass.
- Tests: submit() ValueError on missing job_id; poll() missing-status → failed.

1653 unit tests pass; ruff + ty green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

nextcloud_mcp_server/vector/batch_ocr_store.py

@@ -28,10 +28,11 @@ logger = logging.getLogger(__name__)
 
 @dataclass(frozen=True)
 class BatchOcrJob:
-    """A tracked in-flight batch OCR job."""
+    """A tracked in-flight batch OCR job. A row exists only while pending (terminal
+    jobs are deleted), so there's no stored status — the live status comes from a
+    fresh ``GatewayBatchOcrClient.poll``. ``submitted_at`` anchors the deadline."""
 
     job_id: str
-    status: str
     submitted_at: int
 
 
@@ -67,14 +68,14 @@ class BatchOcrJobStore:
         """The in-flight job for this document+version, or ``None``."""
         async with self._storage.acquire() as db:
             async with db.execute(
-                "SELECT job_id, status, submitted_at FROM batch_ocr_jobs "
+                "SELECT job_id, submitted_at FROM batch_ocr_jobs "
                 "WHERE user_id = ? AND doc_id = ? AND doc_type = ? AND etag = ?",
                 (user_id, doc_id, doc_type, etag),
             ) as cursor:
                 row = await cursor.fetchone()
         if row is None:
             return None
-        return BatchOcrJob(job_id=row[0], status=row[1], submitted_at=int(row[2]))
+        return BatchOcrJob(job_id=row[0], submitted_at=int(row[1]))
 
     async def insert_pending(
         self,
@@ -93,10 +94,10 @@ class BatchOcrJobStore:
         async with self._storage.acquire() as db:
             await db.execute(
                 "INSERT INTO batch_ocr_jobs "
-                "(user_id, doc_id, doc_type, etag, job_id, status, submitted_at, updated_at) "
-                "VALUES (?, ?, ?, ?, ?, ?, ?, ?) "
+                "(user_id, doc_id, doc_type, etag, job_id, submitted_at) "
+                "VALUES (?, ?, ?, ?, ?, ?) "
                 "ON CONFLICT (user_id, doc_id, doc_type, etag) DO NOTHING",
-                (user_id, doc_id, doc_type, etag, job_id, "pending", now, now),
+                (user_id, doc_id, doc_type, etag, job_id, now),
             )
             await db.commit()