Fix AsyncOpenAI proxy compatibility issue

- Create custom httpx.AsyncClient to avoid proxy argument error
- This fixes 'AsyncClient.__init__() got an unexpected keyword argument proxies'

main.py

@@ -230,9 +230,15 @@ async def lifespan(app: FastAPI):
     try:
         if api_key:
             log.info("Initializing OpenRouter client...")
+            # Create custom httpx client to avoid proxy issues
+            import httpx
+            http_client = httpx.AsyncClient(
+                timeout=httpx.Timeout(60.0, connect=10.0),
+            )
             state.llm_client = AsyncOpenAI(
                 api_key=api_key,
                 base_url=config.OPENROUTER_BASE_URL,
+                http_client=http_client,
             )
             log.info(f"OpenRouter client initialized successfully (model: {config.UPSTREAM_MODEL})")
         else: