Add domain schema: instruments, tiles, epochs, and mosaics

[davecoulter]

Summary

• Add 7 domain models (Instrument, Band, Tile, Epoch, Level2Image, Level2Calibration, Level3Mosaic) plus two composite-unique association tables, replacing the Stage 0 placeholder schema with the real astronomical domain model for tile-based mosaicing.
• Enable and index Q3C for native Postgres cone-search on Tile and Level2Image — the extension is enabled via hand-authored migration SQL, but the functional indexes themselves are declared for real on the models, so alembic check stays clean with no autogenerate exclusions needed.
• Fix a Docker dev-environment gap discovered during QA: migrations/ was baked into images at build time (not bind-mounted like src/), so a newly-added migration was invisible inside a running container without a full rebuild. Added a dev-only bind mount on api and removed the now-unused migrations//alembic.ini copy from the worker image (it never runs alembic).
• Update CI to build and run the project's Q3C-enabled Postgres image instead of the stock postgres:16 service, since the new migration requires the extension.
• Process refinements surfaced during review: assessPrompt now applies fully-deterministic fixes directly (with confirmation) instead of always routing them through Gemini; added standing Q3C-indexing and MOC-placement conventions to the Gemini coworking protocol for future domain-model docs.

CLI Verification

All steps completed prior to PR creation via genTests.

• Branch confirmed: feature/domain-models
• Images rebuilt: docker compose build worker_light worker_heavy (Dockerfile changed); api recreated for the new bind mount
• Containers recreated: docker compose up -d api worker_light worker_heavy
• Migrations applied: docker compose exec api alembic upgrade head (confirmed at 0007/head)
• Test suite passed: docker compose exec api uv run pytest --cov=src --cov-fail-under=90 -q — 126 passed, 1 skipped (pre-existing host-only test module, expected inside a container), 98.86% coverage
• Sphinx build passed (local)
• docs/diagrams/infrastructure_topology.md — N/A, no infrastructure topology change

Application QA

All steps completed and verified prior to PR creation via genTests.

• Real reset-db exercised the full migration chain (0001→0007) and reference-data seeding — instruments/bands held exactly the expected NIRCam/MIRI/F150W/F277W rows, confirmed in DBeaver
• Q3C extension and functional indexes confirmed live in the database — pg_extension/pg_indexes showed q3c installed and both ix_tile_q3c/ix_level2_image_q3c present, confirmed in DBeaver
• Uniqueness constraint verified against real infrastructure, not just pytest — a duplicate Instrument insert via DBeaver was rejected with a unique-violation error

🤖 Generated with Claude Code

[github-actions]

Test Results

128 tests  +11   128 ✅ +11   8s ⏱️ -1s
  1 suites ± 0     0 💤 ± 0 
  1 files   ± 0     0 ❌ ± 0 

Results for commit 4b06ccc. ± Comparison against base commit 668a61e.

♻️ This comment has been updated with latest results.