When fetch times out or returns empty after prior data, retain last aircraft
with is_stale=True and render them as black outlines so the display stays
informative rather than blank or crashing.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Implements story 2-7: full main.py with _make_startup_screen(),
_run_one_cycle() with per-phase timing and slow-render warning, and
main() connecting config → bounds → fetcher → renderer → display.
Adds provision.py early-exit when already provisioned. Adds User=root
to both systemd service files. Adds tests/test_main.py (3 new tests,
99 total). Updates scaffold test to allow provisioning.config import
from main.py. All quality gates pass.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Matt Edholm