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>

pyproject.toml

@@ -36,6 +36,7 @@ select = ["E", "F", "I", "TID", "UP"]
 
 [tool.ruff.lint.per-file-ignores]
 # All non-main modules may import from provisioning freely
+"src/planemapper/main.py" = ["TID251"]
 "src/planemapper/provision.py" = ["TID251"]
 "src/planemapper/provisioning/*.py" = ["TID251"]
 # Tests may import from provisioning to test its public API