Build dashboard assets in runtime image

Proof: Include the multistage Dockerfile needed to build operator-dashboard static assets and copy them into the production image so the deployed dashboard backend can serve the new UI.

Assumptions: The dashboard frontend should be built during image creation rather than committed as generated dist artifacts.

Still fake: External alert receiver remains unconfigured; this commit only resolves the live dashboard asset packaging blocker.

Dockerfile

@@ -1,3 +1,12 @@
+FROM node:22-bookworm-slim AS dashboard-builder
+WORKDIR /app
+
+COPY package.json package-lock.json ./
+RUN npm ci
+
+COPY . .
+RUN npm run operator-dashboard:build
+
 FROM node:22-bookworm-slim
 WORKDIR /app
 
@@ -5,6 +14,7 @@ COPY package.json package-lock.json ./
 RUN npm ci --omit=dev
 
 COPY . .
+COPY --from=dashboard-builder /app/src/operator-dashboard/dist ./src/operator-dashboard/dist
 
 ENV NODE_ENV=production
 CMD ["node", "src/apps/near-intents-ingest.mjs"]