0702 — Instance log timestamps follow existing names

Context

The user asked that worker_instance_log follow existing log-table timestamp names. This supersedes the timestamp names in 0701; its write and retention contracts remain unchanged.

Decision

• Keep created_at as the copied worker_instance creation timestamp.
• Use attempted_at for the successful claim or renewal transaction’s timestamp, following the existing binding_config_log distinction between an original timestamp and an attempt timestamp.
• Remove the names instance_created_at and recorded_at. No values are derived differently, and expiry-based cleanup does not change.

Consequences

Snapshot fields retain their source names. Fresh baseline creation and the snapshot insert agree on those names; existing development tables using the previous names require recreation or a local column rename.