Adds draw_home_marker() in overlay.py (red cross at projected home
position) and draw_airspace() in airspace.py (GeoJSON Polygon
boundaries in blue, graceful FileNotFoundError handling). Includes
airspace fixture and three tests covering all acceptance criteria.
All 70 tests pass; ruff check and format clean.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Creates the complete src/planemapper/ layout with all module stubs,
provisioning and renderer subpackages, airports.csv data bundle,
systemd unit files, and full test scaffold. All three quality gates
pass: pytest 12/12, ruff check zero violations, ruff format clean.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Matt Edholm