build(pm): mirror-aware pip/npm registries in PM Dockerfiles (same pattern as api/frontend/bot)

pm/frontend/Dockerfile

@@ -2,8 +2,11 @@
 FROM node:22-alpine AS build
 WORKDIR /app
 
+# NPM_REGISTRY overridable like the ERP frontend image; npmmirror default
+# because registry.npmjs.org is unreachable from this network.
+ARG NPM_REGISTRY=https://registry.npmmirror.com
 COPY package.json package-lock.json ./
-RUN npm ci
+RUN npm config set registry ${NPM_REGISTRY} && npm ci
 
 COPY . .
 RUN npm run build