feat(reset): config wipe, setup screen, and re-exec into provisioning (story 4-2)

Add _handle_reset() and _make_setup_screen() to main.py; integrate ButtonHoldDetector
and LEDController into the radar loop; LED lights immediately on hold, config is wiped,
setup screen shown, then os.execvp hands off to planemapper-provision. Wipe failures
log ERROR and abort without exec. Completes epic-4.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/planemapper/main.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import dataclasses
 import logging
+import os
 import time
 
 import requests
@@ -15,8 +16,10 @@ from planemapper.constants import (
 )
 from planemapper.display import DisplayInterface, WaveshareDisplay
 from planemapper.fetcher import HttpFetcher
+from planemapper.gpio_ctrl import ButtonHoldDetector, LEDController
 from planemapper.models import Aircraft
 from planemapper.provisioning.config import read as read_config
+from planemapper.provisioning.config import wipe as wipe_config
 from planemapper.renderer.basemap import load as load_basemap
 from planemapper.renderer.projection import MapBounds
 from planemapper.renderer.renderer import Renderer
@@ -37,6 +40,32 @@ def _make_startup_screen() -> Image.Image:
     return image
 
 
+def _make_setup_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),
+        "Resetting...",
+        fill=(0, 0, 0),
+        font=font,
+    )
+    return image
+
+
+def _handle_reset(display: DisplayInterface, led: LEDController) -> None:
+    led.on()
+    try:
+        wipe_config()
+    except Exception:
+        log.error("config wipe failed — aborting reset", exc_info=True)
+        led.off()
+        return
+    setup_screen = _make_setup_screen()
+    display.show(setup_screen)
+    os.execvp("planemapper-provision", ["planemapper-provision"])
+
+
 def _run_one_cycle(
     renderer: Renderer,
     fetcher: HttpFetcher,
@@ -89,9 +118,13 @@ def main() -> None:
     fetcher = HttpFetcher()
     renderer = Renderer(base_map, bounds)
     display = WaveshareDisplay()
+    button = ButtonHoldDetector()
+    led = LEDController()
     startup = _make_startup_screen()
     display.show(startup)
     last: list[Aircraft] = []
     while True:
+        if button.check():
+            _handle_reset(display, led)
         last = _run_one_cycle(renderer, fetcher, display, last)
         time.sleep(REFRESH_INTERVAL_S)