Add a way to manually check and request permissions

**Is your feature request related to a problem? Please describe.**
There is actually no way to check if permissions have been granted or manually request them.

**Describe the solution you'd like**
Add a way to manually check and request permissions.

No files, tests, or entry points are named in the issue. First map how the plugin currently handles permissions on each supported platform, then define and implement manual checking and requesting consistently, with tests or platform checks demonstrating both operations.

Written by the indexing model from the issue text.