chore(langgraph): 容器内存限制 4g 提升至 6g，缓解 embedding 同步高峰 OOM 风险

cfc-langgraph/docker-compose.yml

@@ -44,7 +44,7 @@ services:
       - cfc-net
     restart: unless-stopped
     # 内存硬限制：防止 ChromaDB/搜索任务异常膨胀吃满宿主机内存导致整机 OOM
-    mem_limit: 4g
+    mem_limit: 6g
     healthcheck:
       test: ["CMD", "python", "-c", "import urllib.request,sys; sys.exit(0 if urllib.request.urlopen('http://localhost:9000/health', timeout=5).status==200 else 1)"]
       interval: 30s