Implement story 1.1: project scaffold and verified entry points

Creates the complete src/planemapper/ layout with all module stubs,
provisioning and renderer subpackages, airports.csv data bundle,
systemd unit files, and full test scaffold. All three quality gates
pass: pytest 12/12, ruff check zero violations, ruff format clean.

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

src/planemapper/models.py

@@ -0,0 +1,14 @@
+from dataclasses import dataclass
+
+
+@dataclass
+class Aircraft:
+    icao: str
+    lat: float
+    lon: float
+    heading: float = 0.0
+    altitude_ft: int = 0
+    callsign: str = ""
+    category: str = ""
+    is_mlat: bool = False
+    is_stale: bool = False