-`backend/`: FastAPI service. Main app code lives in `backend/app/` with API routes in `backend/app/api/`, data models in `backend/app/models/`, schemas in `backend/app/schemas/`, and service logic in `backend/app/services/`.
-`backend/migrations/`: Alembic migrations (`backend/migrations/versions/` for generated revisions).
-`backend/tests/`: pytest suite (`test_*.py` naming).
-`backend/templates/`: backend-shipped templates used by gateway flows.
-`frontend/`: Next.js app. Routes under `frontend/src/app/`, shared components under `frontend/src/components/`, utilities under `frontend/src/lib/`.
-`frontend/src/api/generated/`: generated API client; regenerate instead of editing by hand.
-`docs/`: contributor and operations docs (start at `docs/README.md`).
- Follow Conventional Commits (seen in history), e.g. `feat: ...`, `fix: ...`, `docs: ...`, `test(core): ...`.
- Keep PRs focused and based on latest `master`.
- Include: what changed, why, test evidence (`make check` or targeted commands), linked issue, and screenshots/logs when UI or operator workflow changes.