Covers the migrated-from-PikaPods case: stale device registrations
carried over by the DB import, server-to-push-proxy connectivity,
OEM battery optimization, and the push-content setting — the likely
causes when only some Android users stop getting background pushes.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AddPmva5bfrUW3MoPriq21
