837c14e081
Scaffolding for the upcoming UI port. Registers the keys the new C++ UI and SpeedState daemon will read/write, and seeds /dev/shm/params defaults at manager start so first-readers don't see missing keys before writers spin up. Keys registered: CarIsMetric, ClearpilotCruiseWarning, ClearpilotCruiseWarningSpeed, ClearpilotHasSpeed, ClearpilotIsMetric, ClearpilotPlayDing, ClearpilotShowHealthMetrics, ClearpilotSpeedDisplay, ClearpilotSpeedLimitDisplay, ClearpilotSpeedUnit, DashcamFrames, DashcamShutdown, DashcamState, IsDaylight, ModelFps, ModelStandby, ModelStandbyTs, ScreenRecorderDebug, ShutdownTouchReset, TelemetryEnabled, VpnEnabled. PERSISTENT registration here is purely a no-op placeholder: the actual storage is /dev/shm/params (tmpfs), which clears on every reboot regardless. Bench-mode keys (Bench*, ClpUiState, LogDirInitialized) not registered yet — they'll come with their respective features.