# Pass 04 — Project, Area and Dataset API

## Goal

Implement first real API slice.

## Implement

- Project create/list/read.
- Area create/list/read for a project.
- Dataset registration endpoint and metadata placeholder contract.
- Validation for GeoJSON polygon areas.
- Contract tests with fixtures.

## Constraints

- No frontend-only fake data assumptions.
- Invalid geometry must produce structured error.
- Dataset upload may be scaffolded, but response contracts must be stable.

## Validation

- API tests.
- Contract fixture comparison where possible.
- Backend import.

## Acceptance

- A client can create a project, add an area, register a dataset and retrieve them.
- Responses follow the documented envelope.
- Execution log updated.