Implement story 1.5: provisioning execution tile download cache validation wifi kill

Add tiles.py, airspace.py, wifi.join_home_wifi, portal /submit route, and rewire
provision.py main loop; all tasks and quality gates pass (56 tests, ruff clean).

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

tests/provisioning/test_tiles.py

@@ -1,2 +1,71 @@
-def test_placeholder() -> None:
-    pass
+import io
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+from PIL import Image
+
+from planemapper.provisioning import ProvisioningError
+from planemapper.provisioning.tiles import (
+    download_and_composite,
+    lat_lon_to_tile,
+    validate_cache,
+)
+
+
+def _make_png_bytes() -> bytes:
+    img = Image.new("RGB", (256, 256), (200, 200, 200))
+    buf = io.BytesIO()
+    img.save(buf, format="PNG")
+    return buf.getvalue()
+
+
+def test_lat_lon_to_tile_london() -> None:
+    x, y = lat_lon_to_tile(51.5, -0.1, 10)
+    assert x == 511
+    assert y == 340
+
+
+def test_download_and_composite(tmp_path: Path) -> None:
+    bg_path = tmp_path / "background.png"
+    mock_resp = MagicMock()
+    mock_resp.content = _make_png_bytes()
+    mock_resp.raise_for_status = MagicMock()
+    with (
+        patch("planemapper.provisioning.tiles.requests.get", return_value=mock_resp),
+        patch("planemapper.provisioning.tiles.BACKGROUND_PATH", bg_path),
+    ):
+        download_and_composite(51.5, -0.1, 100)
+    assert bg_path.exists()
+    with Image.open(bg_path) as img:
+        assert img.size == (800, 480)
+
+
+def test_validate_cache_passes(tmp_path: Path) -> None:
+    bg_path = tmp_path / "background.png"
+    Image.new("RGB", (800, 480), (255, 255, 255)).save(str(bg_path))
+    with patch("planemapper.provisioning.tiles.BACKGROUND_PATH", bg_path):
+        validate_cache()
+
+
+def test_validate_cache_missing(tmp_path: Path) -> None:
+    bg_path = tmp_path / "nonexistent.png"
+    with patch("planemapper.provisioning.tiles.BACKGROUND_PATH", bg_path):
+        with pytest.raises(ProvisioningError, match="not found"):
+            validate_cache()
+
+
+def test_validate_cache_empty(tmp_path: Path) -> None:
+    bg_path = tmp_path / "background.png"
+    bg_path.write_bytes(b"")
+    with patch("planemapper.provisioning.tiles.BACKGROUND_PATH", bg_path):
+        with pytest.raises(ProvisioningError, match="empty"):
+            validate_cache()
+
+
+def test_validate_cache_corrupt(tmp_path: Path) -> None:
+    bg_path = tmp_path / "background.png"
+    bg_path.write_bytes(b"not a png at all")
+    with patch("planemapper.provisioning.tiles.BACKGROUND_PATH", bg_path):
+        with pytest.raises(ProvisioningError, match="not a valid PNG"):
+            validate_cache()