# Pass 02 — Backend Foundation

## Goal

Create the minimal FastAPI backend foundation.

## Implement

- `backend/app/main.py` or equivalent app entrypoint.
- config/settings module using environment variables.
- health endpoint.
- consistent response envelope.
- structured error handling foundation.
- backend test setup.

## Constraints

- Health endpoint must not require database.
- No geospatial logic in route handlers.
- Keep service layer boundaries ready.
- Do not add auth.

## Validation commands

Run the available backend tests/import checks. If package tooling does not exist yet, add minimal test tooling according to dependency policy.

## Acceptance

- App imports cleanly.
- Health endpoint returns deterministic response.
- Tests pass for health/config.
- Execution log updated.