Set unreachable_count to 3 and unreachable_notification_sent to true
on all team servers in subscriptionEnded(), so the existing cleanup
command can pick them up after the 7-day grace period.
Also adds feature tests for the subscription-ended cleanup flow and
casts server IP to string in existing unreachable server tests to fix
type comparison.
Reduce unnecessary job queue pressure and improve subscription sync reliability:
- Cache ServerStorageCheckJob dispatch to only trigger on disk percentage changes
- Rate-limit ConnectProxyToNetworksJob to maximum once per 10 minutes
- Add progress callback support to SyncStripeSubscriptionsJob for UI feedback
- Implement bulk fetching of valid Stripe subscription IDs for efficiency
- Detect and report resubscribed users (same email, different customer ID)
- Fix CleanupUnreachableServers query operator (>= 3 instead of = 3)
- Improve empty subId validation in PushServerUpdateJob
- Optimize relationship access by using properties instead of query methods
- Add comprehensive test coverage for all optimizations
