Audit PRs #55 #57 token usage/account scanning

[cbusillo]

Current Status

Created from parent audit plan #63.

Scope

Review token efficiency scanner and account-correlation fixes for correctness, runtime impact, and whether they influence compaction or agent decisions. Parent: #63. PRs: #55 #57

Review Checklist

• Intent: why did this PR/group exist?
• Surface: what files and runtime paths changed?
• Risk: compaction, token pressure, agent behavior, auth, repo workflow, or other?
• Verdict: keep as-is, keep with rewrite, defer, or drop.
• Validation evidence recorded.