build: switch frontend and worker to Dockerfile images

Frontend/Dockerfile

@@ -0,0 +1,20 @@
+FROM node:22-bookworm-slim
+
+WORKDIR /app/frontend
+
+COPY package*.json ./
+RUN npm ci --legacy-peer-deps
+
+COPY . .
+
+# Build server bundle at image build time.
+RUN npx prisma generate && npm run build
+
+ENV NODE_ENV=production
+ENV NITRO_HOST=0.0.0.0
+ENV NITRO_PORT=3000
+
+EXPOSE 3000
+
+# Keep schema in sync, then start Nitro production server.
+CMD ["bash", "-lc", "npx prisma db push && node .output/server/index.mjs"]