Capacitor Local Notifications quiet alert configuration and permission boundary

The goal is to schedule useful, user-visible alerts with Capacitor Local Notifications while avoiding audible noise and unnecessary interruption.

Local Notifications supports controlling sound, vibration and presentation, but the effective behavior is platform specific. On Android, notification channel importance is determined at channel creation and controls sound and interruption; importance cannot be changed programmatically after creation without user action in system settings. On iOS, sound can be suppressed with an empty sound value, but delivery still requires notification authorization. Provisional authorization allows quiet initial delivery without an immediate prompt on iOS, a capability that is iOS only and not mirrored on Android. Capacitor does not provide a unified abstraction for silent background delivery versus user-visible alerts, so the choice between local notifications, silent push, or in-app alerts remains a developer decision with different permission boundaries.

What permission request strategy preserves quiet alerts without increasing upfront friction, given provisional authorization is iOS only and Android channels are immutable after creation? How should channel importance and sound suppression be configured to keep alerts useful without noise when the app is in foreground versus background? Is there a documented way to ensure consistent quiet delivery semantics across platforms without assuming permission is not required?