Send API (app secret + per-app identity id). Notification: name, text, optional icon, optional action link, urgent flag. Apps register notification kinds (needed for direct push). Inbox in ident. Per-app page per identity: registered since, all notification kinds with push and email switches, one override for all on top. App presets channels, user overrides. Concept: loreana:/media/STORAGE/projects/ident.worldapi.org/CONCEPT.md. Part of #2.