Handle Runtime Permissions

Background: Native [iOS / Android] app, [SwiftUI / Compose]. I need this
permission: [camera / location / notifications / photos / microphone /
contacts]. It's used for: [the feature that needs it].

Use case: Implement the permission flow correctly, including priming,
denial, and the "don't ask again" / restricted states.

Implementation details:
- Request in context, after explaining the value—never on first launch
- iOS: the correct Info.plist usage-description string, the request API
  for this permission, and handling authorized / denied / restricted /
  notDetermined / limited (e.g., limited Photos)
- Android: the runtime-permission request, the rationale UI before
  re-asking, and the permanently-denied path (deep link to Settings)
- A graceful degraded experience when permission is denied
- Re-checking status on return from Settings

Layer & dependencies: Permission status should be observable so the UI
reacts; the feature must function (in a reduced form) without the grant.

Deliverable: The permission flow implementation, the priming UI, handling
of every authorization state, the denied/Settings path, and the
degraded-experience fallback.