v0.4.18

0.4.18 — 2026-06-28

Upgrade notes for admins

• None. This release only changes the backend test suite and CI; the running
  application is unaffected (no migrations, no new runtime env vars).

Changed

• Rebuilt the backend test suite into a layered pytest pyramid under tests/
  (unit · models · services · engines · api · agents · tdmcp),
  growing it from ~50 to 314 tests and total coverage from ~13% to ~45%.
• Added dev/test dependencies: pytest-django, model-bakery, freezegun,
  pytest-mock. Shared fixtures live in tests/conftest.py.
• Raised the coverage floor (fail_under) from 10% to 40%.
• CI's test job now reads DJANGO_DEBUG, DJANGO_SECRET_KEY,
  TETHERDUST_ENCRYPTION_KEY, and INTERNAL_API_SERVICE_TOKEN from repository
  secrets so the Django-backed tests can configure settings without a .env.