Harmont renamed the config dir (.harmont/ -> .hm/) and changed the Python
pipeline DSL: no default_image, and hm.bun(path=...) -> hm.js.project(path,
runtime="bun"). Add a build step alongside test/lint. Commit .gitcafe/ci.yml
(gitcafe routing) so a push actually triggers the workflow.

Verified: cloud build passes end-to-end via source_b64 (build #23, passed).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>