feat: 生产库克隆脚本 + 容器补 Node 运行时

- tools/clone_database.py: 同服务器跨库克隆并建立独立应用账号的 provisioning 脚本。本机与服务器都没有 mysql 客户端，所以走 INSERT...SELECT 而非 dump/reload。刻意只读写命令行指定的两个 schema，且给应用单开账号而不是复用管理员
- Dockerfile: 补 nodejs。douyin/help.py 在模块导入阶段就执行 execjs.compile(libs/douyin.js)，缺 JS 运行时会抛 RuntimeUnavailableError；而 main.py 要导入全部 7 个平台，于是整个应用连带环境自检一起挂掉

已在 192.168.20.220 上验证：7 个平台导入全部通过。

Dockerfile

@@ -26,7 +26,10 @@ ENV PYTHONUNBUFFERED=1 \
 # at import time, and tools/utils.py reaches cv2 through slider_util, so without
 # them the *application* fails to import, not just some image utility. tzdata is
 # here because TZ=Asia/Shanghai is silently ignored without it, which would put
-# every stored timestamp in UTC.
+# every stored timestamp in UTC. nodejs is for PyExecJS: douyin/help.py compiles
+# libs/douyin.js at *import* time, and because main.py imports every platform,
+# that single platform being importable-or-not decides whether the whole app
+# (and the environment self-check) comes up.
 #
 # The pip mirror is set for the same reason as the apt one: this host's route to
 # the public index is slow.
@@ -41,7 +44,7 @@ RUN set -eux; \
     apt-get install -y --no-install-recommends \
         build-essential pkg-config default-libmysqlclient-dev \
         libgl1 libglib2.0-0 libsm6 libxext6 libxrender1 libxcb1 libgomp1 \
-        tzdata; \
+        tzdata nodejs; \
     rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app