update prod env

docker-compose.prod.yml

@@ -1,9 +1,12 @@
 # Production stack for the current codebase: FastAPI + PostgreSQL.
 # The API hard-fails on startup if the database is not reachable, so DB health is required.
 #
-# Base images use DaoCloud public mirror (大陆可访问): docker.io → docker.m.daocloud.io
+# Base images: DaoCloud「增加前缀」镜像（README 推荐，减少 BuildKit 直连 registry-1.docker.io）
 # See https://github.com/DaoCloud/public-image-mirror
 #
+# The ``api`` service is built from ``Dockerfile``: Debian apt → 阿里云, uv/PyPI → 清华,
+# PyTorch CPU wheels / pytorch.org index files → 南大镜像; see Dockerfile for details.
+#
 # Published API port defaults to 38080 on the host (override with API_PORT).
 #
 # GPU (NVIDIA) inference: uv.lock pins torch/torchvision from the PyTorch *CPU* index (see pyproject.toml).
@@ -11,7 +14,7 @@
 # and assign GPUs to the api service (deploy.resources.reservations.devices).
 services:
   db:
-    image: docker.m.daocloud.io/library/postgres:16-alpine
+    image: m.daocloud.io/docker.io/library/postgres:16-alpine
     environment:
       POSTGRES_USER: ${POSTGRES_USER:-postgres}
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:?Set POSTGRES_PASSWORD}