fix: refresh queued conversation history under the session lock (#10238)

* fix: refresh queued conversation history under the session lock

* style: format queued conversation history refresh

* Delete tests/unit/test_queued_conversation_history.py

---------

Co-authored-by: Soulter <37870767+Soulter@users.noreply.github.com>

astrbot/core/astr_main_agent.py

@@ -1440,7 +1440,22 @@ async def collect_initial_request(
                 list(req.contexts) if isinstance(req.contexts, list) else req.contexts
             )
             if req.conversation:
-                req.contexts = json.loads(req.conversation.history)
+                # Handler requests can be prepared before the pipeline acquires
+                # the session lock. Reload the bound conversation here so queued
+                # turns include replies saved while they were waiting.
+                conversation = (
+                    await plugin_context.conversation_manager.get_conversation(
+                        event.unified_msg_origin, req.conversation.cid
+                    )
+                )
+                if conversation is None:
+                    _set_llm_error_message(
+                        event,
+                        "The requested conversation no longer exists. Please send a new message.",
+                    )
+                    return None, None
+                req.conversation = conversation
+                req.contexts = json.loads(conversation.history)
         else:
             req = ProviderRequest()
             req.prompt = ""