Implement retention cleanup scheduling, artefact lifecycle enforcement, and operational safety observability

[kalen-releasedgroup]

Summary

Finish the operational lifecycle work needed to keep the application safe and sustainable in v1.

Scope

• Implement scheduled retention cleanup for artefacts.
• Enforce lifecycle policies for screenshots, DOM snapshots, traces, logs, diagnostic bundles, and generated artefacts.
• Emit structured logs/audit events for cleanup and browser/replay cleanup safety paths.

Requirement Links

• Sections 7.4, 12.7, 13, 16.4
• FR-ADM-004
• Phase 3 exit criteria

Dependencies

• Artefact storage abstraction
• Retention policy model

Exit Criteria

• Expired artefacts are cleaned up according to configured policy.
• Cleanup actions are observable and audited.
• Operational cleanup paths support browser-process and failed-replay recovery.