v1.1.0

• DefaultAbTestingOutboxMessageFactory now stamps event_at (event time, UTC Y-m-d H:i:s) into every payload from an injected Psr\Clock\ClockInterface (default SystemClock) — the moment the event was tracked, not when the worker later exports it. Adds psr/clock as a runtime dependency.
• AbTestingClickHouseRoutes::map() adds the event_at column (after event_id); both are transport-meta columns excluded from the source-of-truth contract.