Feat: add env-driven LLM configuration and smoke test

README.md

@@ -92,9 +92,19 @@ pnpm exec playwright install chromium
 
 - `DATABASE_URL`
 - `JWT_SECRET`
+- `LLM_API_URL`
+- `LLM_API_KEY`
+- `LLM_MODEL`
 - `MEDIA_SERVICE_URL`
 - `VITE_MEDIA_BASE_URL`
 
+LLM 烟雾测试：
+
+```bash
+pnpm test:llm
+pnpm test:llm -- "你好，做个自我介绍"
+```
+
 ## Notes
 
 - 浏览器兼容目标以 Chrome 为主