fix: declare lastAngleDeg as module-level let (fixes TS2304 build error)

Author: Virtual Steering Dev

src/controller/main.ts

@@ -20,7 +20,7 @@ const sensor = new PhoneSensor({ rangeDeg: 25, deadzoneDeg: 2, sensitivity: 1 })
 let network: NetworkManager | null = null;
 let connected = false;
 let lastSteering = 0;
-// const _lastAngleDeg = 0;
+let lastAngleDeg = 0; // eslint-disable-line @typescript-eslint/no-unused-vars
 let lastSend = 0;
 const SEND_INTERVAL = 33; // ~30 Hz
 const packet = { type: 'phone_steering', payload: { s: 0, t: 0 } };