fix: add fallback registries and improve deployment reliability

- Add fallback to official npm/PyPI registries when Chinese mirrors fail
- Fix dev workflow mirror host (127.0.0.1 -> 100.78.131.124)
- Add error handling and diagnostics to build steps
- Fix iPhone UI: make download/delete buttons always visible on mobile
- Add .dockerignore to reduce build context size

dashboard/Dockerfile

@@ -3,7 +3,8 @@ FROM node:20-alpine AS frontend
 WORKDIR /build
 COPY frontend/package.json frontend/package-lock.json* ./
 COPY frontend/ ./
-RUN npm install --registry=https://registry.npmmirror.com && npm run build
+RUN npm install --registry=https://registry.npmmirror.com || npm install
+RUN npm run build
 
 # Stage 2: Python runtime
 FROM python:3.12-slim
@@ -11,7 +12,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends openssh-client
 RUN adduser --disabled-password --no-create-home --gecos "" app
 WORKDIR /app
 COPY backend/requirements.txt .
-RUN pip install --no-cache-dir --index-url https://pypi.tuna.tsinghua.edu.cn/simple -r requirements.txt
+RUN pip install --no-cache-dir --index-url https://pypi.tuna.tsinghua.edu.cn/simple -r requirements.txt || \
+    pip install --no-cache-dir -r requirements.txt
 COPY backend/ ./
 COPY --from=frontend /build/dist /app/static
 RUN chown -R app:app /app