Add persistent car performance analytics

PLAN.md

@@ -237,13 +237,14 @@ reference, not proof for other model years, trims, regions, or software builds.
   or an unrestricted file path. Package and component targets are accepted only through
   strict Android-name validation and fixed `am` or `monkey` argument arrays.
 - Device identity, connection health, display, package inventory, bounded APK install,
-  validated app launch, and the three confirmed ArcSoft vehicle properties are in scope.
+  validated app launch, the three confirmed ArcSoft vehicle properties, and the typed
+  read-only MG Utility battery bridge are in scope.
   State-changing ADB actions are authenticated, CSRF-protected, rate-limited where
   appropriate, audited, and intended for parked use.
 - Do not use ADB or the exported SAIC vehicle service to actuate vehicle hardware in
-  this project. Vehicle telemetry remains read-only. The SAIC AIDL bridge for battery,
-  range, and additional signals remains a later research track until semantics, privacy,
-  and parked-vehicle tests are documented.
+  this project. Vehicle telemetry remains read-only. Battery, range, voltage, consumption,
+  and charging state pass through MG Utility's typed content provider; additional SAIC
+  signals remain a research track until their semantics are documented and tested.
 
 ### Web experience