docs: record v1.0.13 production closure

[RomeoCavazza]

Summary

• record the successful v1.0.13 release and guarded production deploy
• retain the three pre-rollout failures and durable pipeline corrections as audit evidence
• close obsolete mutable-base-image and WebSocket-Origin findings
• reduce the remaining list to genuine time/operator gates

Evidence

• release run 30580631905
• deploy run 30582420348
• backup Job postgres-backup-manual-20260730211238
• exact production image digest and post-deploy probes recorded in the audit