Recovery Record
data class RecoveryRecord(val roomId: String, val cid: String, val reconnectToken: String, val lastEpoch: Long?, val sessionStartTs: Long, val expiresAtMs: Long)
Persisted call-recovery state — surfaced to host apps so a relaunched process can prompt the user to rejoin an in-flight call instead of silently dropping them on the home screen.
Backed by app-private SharedPreferences; cleared on clean leave, room_ended, or INVALID_RECONNECT_TOKEN.