feat: add Paperless orphan cleanup endpoint

- POST /maintenance/cleanup/paperless - detect and clean orphaned Paperless documents
- Checks indexed documents against Paperless API
- Removes vectors and graph nodes for deleted documents
- Supports dry_run mode for preview

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/services/vector_service.py

@@ -389,6 +389,39 @@ class VectorService:
             logger.error(f"Failed to delete chunks for document {document_id}: {e}", exc_info=True)
             return 0
 
+    async def delete_paperless_document_chunks(
+        self,
+        paperless_id: int,
+        user: str
+    ) -> int:
+        """
+        Delete all chunks for a Paperless document.
+
+        Args:
+            paperless_id: Paperless-ngx document ID
+            user: User identifier
+
+        Returns:
+            Number of chunks deleted
+        """
+        collection_name = get_qdrant_collection_name(user)
+
+        try:
+            deleted_count = await self.qdrant.delete_by_filter(
+                collection_name=collection_name,
+                filter_conditions={
+                    "doc_type": "document",
+                    "paperless_id": paperless_id
+                }
+            )
+
+            logger.info(f"Deleted chunks for Paperless document {paperless_id}")
+            return deleted_count
+
+        except Exception as e:
+            logger.error(f"Failed to delete chunks for Paperless document {paperless_id}: {e}", exc_info=True)
+            return 0
+
     async def delete_collection_chunks(
         self,
         collection_id: str,