Add Strapi CMS with Article and Category content types

Article is deliberately minimal: title, slug, Markdown body, cover image and
category. No Author content type — the administrator is the only writer.

The bootstrap hook grants the Public role find/findOne on the two content types
and disables self-registration, so the public API is read-only and the site has
no front-end accounts.

cms/Dockerfile

@@ -0,0 +1,18 @@
+FROM node:22-alpine AS build
+WORKDIR /app
+# Sharp (image processing) needs these at install time on Alpine.
+RUN apk add --no-cache build-base python3 vips-dev
+COPY package*.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+
+FROM node:22-alpine AS runtime
+WORKDIR /app
+RUN apk add --no-cache vips
+ENV NODE_ENV=production
+COPY --from=build /app /app
+RUN mkdir -p public/uploads && chown -R node:node /app
+USER node
+EXPOSE 1337
+CMD ["npm", "run", "start"]