Chameleon

Attestation-gated auto-pass (roadmap #7). The session attestation exists so
downstream gates can raise scrutiny, but the auto-pass router ignored it — a diff
produced with verification off, a degraded correctness judge, and inline
overrides auto-passed on identical terms to a fully-governed one. This closes
that asymmetry. Advisory (the router never blocks; it recommends auto-pass vs
human review).

Added

• Session-governance signals in the auto-pass router (default on; kill with
  CHAMELEON_AUTOPASS_ATTESTATION=0). get_autopass_verdict now loads the recent
  session attestations, attributes them to the branch diff by FILE OVERLAP
  (repo_id is already the ledger scope), and folds three governance signals in
  RAISE-ONLY: post-edit verification suppressed while the diff was written, the
  correctness judge spawn degraded (a real failure, NOT the routine low-risk skip
  or cooldown re-verify — those would route nearly everything to a human and
  defeat auto-pass), or a chameleon-ignore override fired on one of the diff's own
  files. Each adds a soft (→ elevated) needs-human reason. Strictly raise-only: no
  attestation match leaves the verdict exactly as before, so a forged clean record
  buys nothing and an un-attested change is classified identically to today.
  Tool-time only, fail-open (any read error leaves the coverage all-clear).