feat(07-02): Add CI/CD deployment scripts

- scripts/deploy.sh: Full deploy flow with fresh builds (--no-cache)
- scripts/build-check.sh: Pre-flight staleness check
- Docker labels for build tracking (git commit + timestamp)
- Prevents stale container bug from recurring

backend/Dockerfile

@@ -1,5 +1,10 @@
 FROM node:20-alpine
 
+ARG GIT_COMMIT=unknown
+ARG BUILD_DATE=unknown
+LABEL org.opencontainers.image.revision=$GIT_COMMIT \
+      org.opencontainers.image.created=$BUILD_DATE
+
 WORKDIR /app
 
 COPY package*.json ./