feat: enhance chat history loading with new hooks and UI components (#2338)

* Refactor API fetch calls to use a unified fetch function; enhance chat history loading with new hooks and UI components

- Replaced `fetchWithAuth` with a generic `fetch` function across various API modules for consistency.
- Updated `useThreadStream` and `useThreadHistory` hooks to manage chat history loading, including loading states and pagination.
- Introduced `LoadMoreHistoryIndicator` component for better user experience when loading more chat history.
- Enhanced message handling in `MessageList` to accommodate new loading states and history management.
- Added support for run messages in the thread context, improving the overall message handling logic.
- Updated translations for loading indicators in English and Chinese.

* Fix test assertions for run ordering in RunManager tests

- Updated assertions in `test_list_by_thread` to reflect correct ordering of runs.
- Modified `test_list_by_thread_is_stable_when_timestamps_tie` to ensure stable ordering when timestamps are tied.

backend/app/gateway/routers/thread_runs.py

@@ -54,7 +54,6 @@ class RunCreateRequest(BaseModel):
     after_seconds: float | None = Field(default=None, description="Delayed execution")
     if_not_exists: Literal["reject", "create"] = Field(default="create", description="Thread creation policy")
     feedback_keys: list[str] | None = Field(default=None, description="LangSmith feedback keys")
-    follow_up_to_run_id: str | None = Field(default=None, description="Run ID this message follows up on. Auto-detected from latest successful run if not provided.")
 
 
 class RunResponse(BaseModel):
@@ -312,11 +311,15 @@ async def list_thread_messages(
         if i in last_ai_indices:
             run_id = msg["run_id"]
             fb = feedback_map.get(run_id)
-            msg["feedback"] = {
-                "feedback_id": fb["feedback_id"],
-                "rating": fb["rating"],
-                "comment": fb.get("comment"),
-            } if fb else None
+            msg["feedback"] = (
+                {
+                    "feedback_id": fb["feedback_id"],
+                    "rating": fb["rating"],
+                    "comment": fb.get("comment"),
+                }
+                if fb
+                else None
+            )
         else:
             msg["feedback"] = None
 
@@ -339,7 +342,8 @@ async def list_run_messages(
     """
     event_store = get_run_event_store(request)
     rows = await event_store.list_messages_by_run(
-        thread_id, run_id,
+        thread_id,
+        run_id,
         limit=limit + 1,
         before_seq=before_seq,
         after_seq=after_seq,