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>

src/planemapper/main.py

@@ -1,8 +1,73 @@
+from __future__ import annotations
+
 import logging
+import time
+
+from PIL import Image, ImageDraw, ImageFont
+
+from planemapper.constants import (
+    DISPLAY_HEIGHT,
+    DISPLAY_WIDTH,
+    REFRESH_INTERVAL_S,
+    RENDER_WARN_S,
+)
+from planemapper.display import DisplayInterface, WaveshareDisplay
+from planemapper.fetcher import HttpFetcher
+from planemapper.provisioning.config import read as read_config
+from planemapper.renderer.basemap import load as load_basemap
+from planemapper.renderer.projection import MapBounds
+from planemapper.renderer.renderer import Renderer
 
 log = logging.getLogger(__name__)
 
 
+def _make_startup_screen() -> Image.Image:
+    image = Image.new("RGB", (DISPLAY_WIDTH, DISPLAY_HEIGHT), color=(255, 255, 255))
+    draw = ImageDraw.Draw(image)
+    font = ImageFont.load_default()
+    draw.text(
+        (DISPLAY_WIDTH // 2 - 60, DISPLAY_HEIGHT // 2),
+        "planeMapper starting...",
+        fill=(0, 0, 0),
+        font=font,
+    )
+    return image
+
+
+def _run_one_cycle(renderer: Renderer, fetcher: HttpFetcher, display: DisplayInterface) -> None:
+    t0 = time.monotonic()
+    aircraft_list = fetcher.fetch()
+    t1 = time.monotonic()
+    image = renderer.render(aircraft_list)
+    t2 = time.monotonic()
+    display.show(image)
+    t3 = time.monotonic()
+    total = t3 - t0
+    log.info(
+        "cycle: fetch=%.1fs render=%.1fs spi=%.1fs total=%.1fs",
+        t1 - t0,
+        t2 - t1,
+        t3 - t2,
+        total,
+    )
+    if total > RENDER_WARN_S:
+        log.warning("render slow: %.1fs > %ds threshold", total, RENDER_WARN_S)
+
+
 def main() -> None:
     logging.basicConfig(level=logging.INFO)
-    log.info("not implemented")
+    cfg = read_config()
+    bounds = MapBounds(
+        home_lat=cfg["home_lat"],
+        home_lon=cfg["home_lon"],
+        radius_nm=cfg["coverage_radius_nm"],
+    )
+    base_map = load_basemap()
+    fetcher = HttpFetcher()
+    renderer = Renderer(base_map, bounds)
+    display = WaveshareDisplay()
+    startup = _make_startup_screen()
+    display.show(startup)
+    while True:
+        _run_one_cycle(renderer, fetcher, display)
+        time.sleep(REFRESH_INTERVAL_S)

src/planemapper/provision.py

@@ -1,6 +1,6 @@
 import logging
 
-from planemapper.provisioning import ProvisioningError, wifi
+from planemapper.provisioning import ProvisioningError, config, wifi
 from planemapper.provisioning.portal import app
 
 log = logging.getLogger(__name__)
@@ -16,6 +16,13 @@ def _reset_to_portal_state() -> None:
 
 def main() -> None:
     logging.basicConfig(level=logging.INFO)
+    try:
+        cfg = config.read()
+        if cfg.get("provisioned"):
+            log.info("already provisioned — exiting")
+            return
+    except FileNotFoundError:
+        pass  # no config — proceed to portal
     provisioned = False
     while not provisioned:
         try: