…7523)

[ENG-7523](https://stacklet.atlassian.net/browse/ENG-7523)

### what

- Patch `prodLogger` in `cubejs-server-core` to unconditionally emit
  "Performing query completed" messages regardless of log level
- Introduce `scripts/build-docker.sh` to compile locally patched packages
  and stage their `dist/` output into
  `packages/cubejs-docker/stacklet-patches/` before `docker build`
- Update `packages/cubejs-docker/latest.Dockerfile` to overlay any
  `*-dist/` directories found in `stacklet-patches/` onto the
  npm-installed package versions
- Add `packages/cubejs-docker/DEVELOPMENT.md` documenting the Stacklet
  build workflow

### why

The CloudWatch log metric filter in `platform-cubejs-schemas` relies on
"Performing query completed" messages to track pre-aggregation runs, but
the upstream logger gates them on log level. Our goal is to preserve these
specific log lines needed for metrics without the expense of running at
trace-level logging across the board. The Docker image installs packages
from npm via `yarn install --prod`, so local TypeScript changes compiled
into `packages/*/dist/` are silently ignored. The build script and
Dockerfile overlay ensure the patched logger is always present in the
resulting image.

### testing

Run `./scripts/build-docker.sh <tag>` and verify:
  docker run --rm <tag> grep -c "Performing query completed" \
    /cube/node_modules/@cubejs-backend/server-core/dist/src/core/logger.js
Expected output: 2

### docs

Updated `packages/cubejs-docker/DEVELOPMENT.md` with Stacklet build
instructions and pattern for adding future patched packages.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>