There was no in-app control over notifications. Add a Notifications
preference screen under Settings offering:
- "Show download progress": when off, downloads/updates no longer post
per-tick progress; a single quiet foreground notification keeps the
work running in the background (honouring the mandatory FGS rule).
- Deep links into each notification category's system settings (O+) so
users can tune sound and importance per channel.
- A shortcut to enable notifications when they're turned off at the
system level, so the screen degrades gracefully.
The download worker reads the progress preference live, keeping its
foreground notification minimal and skipping progress refreshes when
the user has opted out. POST_NOTIFICATIONS is already handled by the
onboarding permission flow, so no duplicate prompt is added here.
a660983438