Add PostgreSQL-backed background worker

Dockerfile

@@ -6,10 +6,19 @@ WORKDIR /app
 FROM base AS install
 COPY package.json bun.lock ./
 COPY apps/web/package.json apps/web/package.json
+COPY apps/worker/package.json apps/worker/package.json
 COPY apps/mobile/package.json apps/mobile/package.json
 COPY packages/domain/package.json packages/domain/package.json
 RUN bun install --frozen-lockfile --filter @beenvoice/web
 
+FROM base AS worker-install
+COPY package.json bun.lock ./
+COPY apps/web/package.json apps/web/package.json
+COPY apps/worker/package.json apps/worker/package.json
+COPY apps/mobile/package.json apps/mobile/package.json
+COPY packages/domain/package.json packages/domain/package.json
+RUN bun install --frozen-lockfile --filter @beenvoice/worker
+
 # Next's production build runs under Node because Bun can fail during the
 # page-data worker phase on Linux arm64. Dependencies still come from Bun.
 FROM node:22-bookworm-slim AS build
@@ -55,3 +64,21 @@ USER bun
 EXPOSE 3000
 WORKDIR /app/apps/web
 CMD ["sh", "-c", "bun src/server/db/migrate.ts && bun run start"]
+
+FROM base AS worker
+ENV NODE_ENV=production \
+    NEXT_TELEMETRY_DISABLED=1
+
+COPY --from=worker-install /app ./
+COPY apps/web/src ./apps/web/src
+COPY apps/web/tsconfig.json ./apps/web/tsconfig.json
+COPY apps/worker ./apps/worker
+COPY packages/domain ./packages/domain
+RUN ln -s ../worker/node_modules apps/web/node_modules
+
+USER bun
+WORKDIR /app/apps/worker
+CMD ["bun", "run", "start"]
+
+# Keep the web application as the default Dockerfile target.
+FROM release AS final