bug: wallet backup retries every 10s while the homeserver is down #1746

What happened?

While the Pubky homeserver is unreachable, the WALLET backup fails and retries every 10 s:

WARN [BackupRepo.kt:691] Retrying backup for: 'WALLET' in '10s' [AppError='code=transport_error, context=get_paykit_app_registry: fetch Paykit App Registry']

METADATA, ACTIVITY and WIDGETS back up normally during the same outage. The WALLET backup depends on fetching the Paykit App Registry from the homeserver, so a homeserver outage blocks it and the 10 s retry never backs off.

Expected behavior

Either the WALLET backup does not depend on the homeserver, or its retries back off while the homeserver stays unreachable.

Steps to Reproduce

1. Use a wallet with a Pubky identity.
2. Make the homeserver unreachable: block or hold traffic to it, for example through an HTTP proxy that blackholes the homeserver host.
3. Trigger a wallet change that schedules a WALLET backup.
4. The log repeats the line above every 10 s for as long as the outage lasts.

Logs / Screenshots / Recordings

Seen on master 1337f12 and on #1684 head fd617bf, during that PR's device gate.

Bitkit Version

master 1337f12

Device / OS

Pixel_9 emulator (Android 16), dev regtest/staging.

Reproducibility

Every time.