tools: visual-review screenshot pipeline

- AGigLineShotActor (dev-only): walks a fixed camera list in -game mode,
  captures via FScreenshotRequest, quits. Test content only.
- ue_build_review_map.py builds /Game/Test/ReviewMap from current content
  (gray floor, key light, sky, MPFB character, 1 m scale cubes).
- render_screenshots.sh: build map -> run game -> collect PNGs into
  gitignored Screenshots/.
- Screenshots/README.md (committed) describes each capture with approval
  state; AGENTS.md gains the visual-review instructions.

AGENTS.md

@@ -77,6 +77,17 @@ Always use a consistent scale test, named export presets, and repeatable import
 - Keep restricted assets out of the public repository; prefer redistributable replacements.
 - Review Epic distribution requirements before publishing builds.
 
+## Visual review (screenshots)
+
+Any change that affects the game's appearance — meshes, materials, lighting, levels, character, camera, post-processing — must be rendered for human review:
+
+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.
+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`.
+
 ## Roadmap
 
 The living roadmap with per-version task checklists is in **[ROADMAP.md](ROADMAP.md)**.