chore: keep review screenshots off the repository

AGENTS.md requires the PNGs to stay on disk with only Screenshots/README.md
tracked. Four shots had been committed; they are removed from the index and the
ignore rule restored, so the next review run cannot add binaries by accident.

.gitignore

@@ -57,3 +57,7 @@ Thumbs.db
 
 # Unreal per-project build artefacts (FileOpenOrder logs and the like)
 Build/
+
+# Screenshots: only the review README is tracked; PNGs stay on disk
+/Screenshots/
+!/Screenshots/README.md