team-operator: Add Kubernetes events for state transitions

[ian-flores]

Summary

Emit Kubernetes events on lifecycle transitions, dependency waits, and reconcile failures so customer admins can see operator state via kubectl describe.

Acceptance Criteria

• Normal events on first-time transitions: Created, Ready, Updated
• Warning events on recoverable problems: DependencyPending, WaitingForSecret, WaitingForCRD
• Warning events on hard failures: ReconcileError, ConfigInvalid, AuthenticationFailed
• Sub-dispatch failures emit on the per-product CR, not on Site
• --observability-events-enabled=false suppresses all emission

Design: #7 (comment) (Phase 2 section)

Phase 2 of three. Phase 1: #7. Phase 3: #133.