WalletForegroundService
Foreground service that keeps a backgrounded wallet operation (send, dust registration, contract call — or any com.midnight.kuira.sdk.MidnightSdk.runForegroundOperation) OR a wallet sync alive, and shows its progress as an Android Live-Update notification (#261-264, generalizing the #235 dust-sync service).
It does NOT run the work — operations run on the SDK's subscriptionScope, syncs on the wallet's tracker; this service exists so the OS doesn't kill the process while the app is backgrounded, and to surface progress. Started by attach's observer when an operation or sync is in flight; self-manages (updates on change, stops on foreground-idle / completion / session lock). An in-flight operation takes precedence over a sync for the notification text.
Host opt-in: call attach once from Application.onCreate. The <service> + permissions are declared in this module's manifest and merge into the host.