feat(2-7): operational radar loop, startup screen, and systemd wiring

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>

systemd/planemapper-provision.service

@@ -5,6 +5,7 @@ After=network.target
 [Service]
 Type=oneshot
 ExecStart=/usr/local/bin/planemapper-provision
+User=root
 StandardOutput=journal
 StandardError=journal
 RemainAfterExit=yes