chore(#4024): drop docs/ui-ux/review-shots/ trifecta scratch from the release diff

These 5 PNGs (722K) are the agent trifecta review-pass screenshots copied into
the worktree so the Opus gate could read them — review scratch, not durable UX
evidence. The intended evidence lives in docs/ui-ux/evidence/pr4024-*.png and is
kept. Mirrors the .review-crops/ cleanup; gitignore the dir so review scratch
can't leak into a release diff. No code or test change.

.gitignore

@@ -69,3 +69,4 @@ graphify-out/
 # Dev-only lint tooling (ESLint runtime-error guard) — see TESTING.md
 node_modules/
 package-lock.json
+docs/ui-ux/review-shots/