fix(backup): install pg_dump (postgresql16-client) in app + worker images

The DR backup engine spawns `pg_dump` (backup.service.ts), but neither
runner image installed a postgres client — so producing a bundle fails
in prod with ENOENT (only worked in dev, where the host has pg_dump).
Surfaced by testing the feature on the live prod container.

Add `postgresql16-client` (pg_dump 16.x, matched to the postgres:16
server) to the runner stage of Dockerfile (crm-app: on-demand export +
"back up now") and Dockerfile.worker (scheduled backup-push cron).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -59,6 +59,9 @@ RUN apk add --no-cache --virtual .merge-deps rsync \
  && rsync -a --ignore-existing /opt/prod-node-modules/ ./node_modules/ \
  && rm -rf /opt/prod-node-modules \
  && apk del .merge-deps
+# pg_dump for the backup/DR bundle engine (src/lib/services/backup.service.ts
+# spawns `pg_dump`). Version pinned to match the postgres:16 server.
+RUN apk add --no-cache postgresql16-client
 USER nextjs
 EXPOSE 3000
 HEALTHCHECK --interval=30s --timeout=5s --start-period=20s --retries=3 \