slim down image: python:3.10-slim base + python-based healthcheck

Base python:3.10 (917MB) dominated the 986MB image and kaniko's snapshot/push time. All deps are pure-python/wheels, so slim works without build tools. Replace the curl healthcheck (curl absent in slim) with a stdlib urllib check.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.10
+FROM python:3.10-slim
 
 #
 WORKDIR /code

docker-compose.yaml

@@ -22,7 +22,7 @@ services:
       - OFFICE_XBOT_VIEW_ID=${OFFICE_XBOT_VIEW_ID}
       - TZ=Asia/Shanghai
     healthcheck:
-      test: ["CMD", "curl", "-f", "http://127.0.0.1:8080/index"]
+      test: ["CMD", "python", "-c", "import urllib.request; urllib.request.urlopen('http://127.0.0.1:8080/index')"]
       interval: 30s
       timeout: 10s
       retries: 3