fix: add @OverRide on LLMMetricsHooks.on_llm_end for pyright

Author: x

src/agentex/lib/core/observability/llm_metrics_hooks.py

@@ -9,6 +9,7 @@
 from __future__ import annotations
 
 from typing import Any
+from typing_extensions import override
 
 from agents import Agent, RunHooks, ModelResponse, RunContextWrapper
 
@@ -18,6 +19,7 @@
 class LLMMetricsHooks(RunHooks):
     """Emits ``agentex.llm.requests`` + token counters on every LLM call."""
 
+    @override
     async def on_llm_end(
         self,
         context: RunContextWrapper[Any],