repo: allow screenshots in the repository

- Drop the /Screenshots/* gitignore exclusion so review PNGs are committed
  (LFS-tracked) alongside the review README.
- AGENTS.md Visual review: PNGs are now committed, not kept only on disk.
- 13 review/demo screenshots tracked (25 MB LFS).

.gitignore

@@ -52,10 +52,8 @@ Thumbs.db
 # Blender/Blosm working caches
 /Art/blender/.cache/
 
-# Rendered screenshots for visual review — generated locally, never committed.
-# Keeps only the review README (see AGENTS.md Visual review).
-/Screenshots/*
-!/Screenshots/README.md
+# Rendered screenshots for visual review — committed with the repo (see
+# AGENTS.md Visual review) so reviewers see what the build rendered.
 
 # Scratch files
 .tmp-*