fix: address code review findings in files, transport, and models

- Fix files.py fetch_next to use after_id instead of page for IdCursorPage
- Remove dead sync close() body in AsyncTransport (AsyncClient has no sync close)
- Handle string agent values in Session.agent_id property

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: foleydang

dashscope/agentstudio/resources/files.py

@@ -190,7 +190,7 @@ def list(
         def fetch_next(token: str) -> IdCursorPage[File]:
             return self.list(
                 limit=limit,
-                page=token,
+                after_id=token,
                 scope_id=scope_id,
             )
 
@@ -291,7 +291,7 @@ async def list(
         async def fetch_next(token: str) -> AsyncIdCursorPage[File]:
             return await self.list(
                 limit=limit,
-                page=token,
+                after_id=token,
                 scope_id=scope_id,
             )
 

dashscope/agentstudio/transport.py

@@ -664,12 +664,7 @@ async def _parse(self, resp: httpx.Response) -> APIResponse:
         )
 
     def close(self) -> None:
-        """Best-effort synchronous close (for __del__ / GC safety)."""
-        if self._owns_client:
-            try:
-                self._client.close()
-            except Exception:
-                pass
+        """No-op: AsyncClient requires async cleanup via aclose()."""
 
     async def aclose(self) -> None:
         if self._owns_client:

dashscope/agentstudio/types/models.py

@@ -475,7 +475,9 @@ def __init__(self, **kwargs: Any) -> None:
     @property
     def agent_id(self) -> Optional[str]:
         a = self.agent
-        return a.id if isinstance(a, Agent) else None
+        if isinstance(a, Agent):
+            return a.id
+        return a if isinstance(a, str) else None
 
     @property
     def agent_version(self) -> Optional[int]: