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).

AGENTS.md

@@ -100,7 +100,7 @@ Any change that affects the game's appearance — meshes, materials, lighting, l
 
 1. Run `Tools/render_screenshots.sh` (rebuilds `Game/GigLine/Content/Test/ReviewMap.umap` from current content, runs the game on it, captures the fixed camera list, copies the PNGs into `Screenshots/`).
 2. Update `Screenshots/README.md`: one row per screenshot with what it shows and an approval state; describe any new shots or scene changes in the same change.
-3. The PNGs are **never committed** — `.gitignore` keeps only `Screenshots/README.md`. Review happens on disk.
+3. The PNGs **are committed** so reviewers see exactly what the build rendered (`.gitignore` does not exclude them). Keep them in sync with this README: drop retired shots in the same change.
 4. Wait for the user's approval before treating a visual change as done; record approval by ticking the table in `Screenshots/README.md`.
 
 New content that needs a different camera angle gets a new entry in the shot list in `Tools/ue_build_review_map.py`.