Chameleon

Fixed

• The turn-end duplication review re-flagged pre-existing duplications on every
  turn. It scanned every function in a session-edited file and deduped only on
  (file, content-digest), so any edit anywhere in a file busted the digest and
  re-surfaced every duplication in it, including methods the author never touched
  and had already chosen to keep. Two changes fix it, both at the shared gather
  layer so the standalone gate and the multi-lens lens both benefit:
  • Diff-scoping: a function is only considered when its line span overlaps
    what the session actually changed (vs HEAD). A committed, pre-existing
    duplicate the turn did not touch is no longer flagged just because the file
    was edited elsewhere. A brand-new file counts as fully changed; a non-git
    repo (or unreadable diff) falls back to whole-file scanning, so nothing
    regresses.
  • Per-finding session dedup: a specific duplication pair surfaces at most
    once per session. Re-editing the file (a new digest) can no longer re-flag a
    duplication the author already saw. The marker is line-independent and aged
    out at SessionStart with the other per-session markers.