Mock interview: the support desk at Sunwaai

A full 50-minute model interview: Meghna sizes a multi-tenant help desk, feeds near-real-time ticket search from an outbox stream with external versions, makes search permission-aware and closes a stale-permission snippet leak, fires SLA timers once, tames a 200,000-ticket complaint storm with quotas and incident mode, and answers an EU residency request by reusing the tenant partition key.