# Codex Pass 03 — Project and Area API

## Goal

Implement persisted project and area management.

## Must implement

- create/list/read/update project endpoints;
- create/list/read area endpoints;
- polygon validation;
- area calculation with explicit units;
- API schemas;
- service layer;
- tests for happy path and invalid polygon.

## UI not required

This pass is backend-only unless otherwise requested.

## Output

Use `docs/M6_FINAL_HANDOFF_TEMPLATE.md`.