Chameleon

Correctness judge: much higher recall on the defect classes it exists to catch,
with no false-positive cost. The turn-end correctness reviewer (and the
multi-lens correctness lens that shares its prompt) was missing unguarded
dereferences, dropped awaits, and off-by-one errors on real repos. Two prompt
changes fix that, validated on a real TypeScript and a real Ruby repo.

Changed

• Correctness reviewer now works through an explicit defect checklist. The
  prompt enumerates the defects most often missed and makes the reviewer clear
  each dereference, index, and condition in the diff: optional/absent-on-miss
  lookups dereferenced without a guard (Map.get / .find / .find_by / hash
  index), nilable receivers used without ?. / &. / a guard, dropped awaits,
  off-by-one and index-bounds errors, assignment-in-condition, unreachable code,
  and inverted conditions. A reminder to apply the checklist is re-anchored next
  to each diff so it stays salient on context-heavy repos, and it names the safe
  forms (explicit
  default lookups like fetch(k, default), optional chaining, and an earlier
  early-return guard even when it sits outside the diff) so guarded code is not
  flagged.

• Correctness-only prompt no longer carries team-idiom guidance or a sibling
  witness by default. An interleaved A/B on both repos found that injecting
  the convention guidance and canonical excerpt into this bug-only prompt lowers
  correctness recall with no false-positive benefit: the style context crowds
  out the bug signal the reviewer is already told to ignore for style. The
  correctness lens now gets only correctness-relevant context (the checklist,
  the user's checkable intent tokens, the committed-caller facts, and the diff).
  A new include_style_context flag on build_prompt (default off) lets a
  future style-aware lens opt back in.