Confidence lifecycle management.
Memories that haven't been retrieved in 30+ days are automatically marked "stale". If they're recalled again, they wake back up to "observed" so they can earn trust again.
Summary
Functions
Resolve the effective confidence state for an entry. Computed on-read, no DB write.
Mark an entry as verified (e.g., after positive outcome feedback).
Wake up stale entries when retrieved. Returns number of entries woken up.