Add Gitea build, container tests and registry publication

agiledancers-fe/Dockerfile

@@ -0,0 +1,18 @@
+FROM node:24.15.0-bookworm AS build
+WORKDIR /workspace
+COPY package.json package-lock.json ./
+RUN npm ci
+COPY . .
+RUN npm test && npm run build
+
+FROM nginx:1.28-alpine AS runtime
+ENV BACKEND_UPSTREAM=backend:8080
+COPY nginx/default.conf.template /etc/nginx/templates/default.conf.template
+EXPOSE 8080
+
+# CI supplies the production output it has already built and tested.
+FROM runtime AS prebuilt
+COPY dist/agiledancers-fe/browser/ /usr/share/nginx/html/
+
+FROM runtime AS standalone
+COPY --from=build /workspace/dist/agiledancers-fe/browser/ /usr/share/nginx/html/