fix: drop unrecognized stream_metadata, align sort and page_count

- Remove stream_metadata from chat/completions payloads — the server's
  ChatCompletionRequest model has no such field; it was silently ignored.
- Local list_documents tie-breaker: rowid DESC → doc_id ASC, matching
  the server's "createdAt" DESC, "id" ASC ordering.
- Cloud get_document: skip page_count when pageNum is 0 (server returns
  0 for NULL, meaning "not yet computed", not "zero pages").

pageindex/backend/cloud.py

@@ -307,7 +307,7 @@ class CloudBackend:
             "status": resp.get("status", ""),
             "structure": self._normalize_tree(raw_tree, max_page=page_num),
         }
-        if page_num is not None:
+        if page_num:
             result["page_count"] = page_num
         return result
 
@@ -508,7 +508,6 @@ class CloudBackend:
                         "messages": [{"role": "user", "content": question}],
                         "doc_id": doc_id,
                         "stream": True,
-                        "stream_metadata": True,
                     },
                     stream=True,
                     timeout=120,

pageindex/cloud_api.py

@@ -169,13 +169,6 @@ class LegacyCloudAPI:
             payload["temperature"] = temperature
         if enable_citations:
             payload["enable_citations"] = enable_citations
-        # Forward stream_metadata so the wire request matches the caller's intent
-        # (and stays correct if the server ever gates metadata chunks behind it),
-        # mirroring the modern CloudBackend which always sends it. It only affects
-        # streaming responses, where it selects the raw dict-chunk parser below.
-        if stream_metadata:
-            payload["stream_metadata"] = stream_metadata
-
         # Non-streaming completions return no bytes until server-side
         # generation finishes — far longer than the default 30s read timeout.
         response = self._request(

pageindex/storage/sqlite.py

@@ -265,7 +265,7 @@ class SQLiteStorage:
     def list_documents(self, collection: str) -> list[dict]:
         conn = self._get_conn()
         rows = conn.execute(
-            "SELECT doc_id, doc_name, doc_description, doc_type FROM documents WHERE collection_name = ? ORDER BY created_at DESC, rowid DESC",
+            "SELECT doc_id, doc_name, doc_description, doc_type FROM documents WHERE collection_name = ? ORDER BY created_at DESC, doc_id ASC",
             (collection,),
         ).fetchall()
         return [{"doc_id": r[0], "doc_name": r[1], "doc_description": r[2] or "", "doc_type": r[3]} for r in rows]