docs(codex): publish Build Small submission package
Publish the tested canonical hackathon UI/API gateway, concrete-support prompt pipeline, build article, demo script, social copy, and submission metadata.
Ready for organization review. This PR supersedes #3. Local verification: 151 tests passed and Ruff passed. The owner runtime and both Modal services are live; after merge, the organization Space will serve the canonical UI and preserve streamed intake/forest responses without requiring an organization secret. Please merge this PR to complete the move.
Final verification update: 155 tests passed, Ruff passed, and the PR has no conflicts. The exact gateway mode in this PR completed a live test-score flow through the production runtime with five streamed clearings and a final complete event. A separate Modal image check returned a valid PNG data URI. The remaining action is organization-admin merge.