tools: add screenshot judge script using OpenRouter vision

- Tools/judge_screenshot.py: judges a screenshot against an expected-scene
  description via OpenRouter multimodal image understanding, reading
  OPENROUTER_API_KEY from the ignored .env. --image+--expect for one shot,
  --shots to run every review shot in Screenshots/README.md. Returns a
  {verdict, confidence, reason, missing} JSON.
- Documented in AGENTS.md (Visual review pre-check step) and Tools/README.md;
  recorded the OpenRouter payload format gotcha in MEMORY.md.

MEMORY.md

@@ -147,3 +147,8 @@ Scope: facts and traps that cost time to establish. Planned work lives in [TODO.
 - **A per-pixel `struct.pack` loop over `img.pixels` is catastrophic in headless Blender** (256² took 25 s). Blender ships numpy: read `img.pixels[:]` once into a float array, reshape `(h,w,4)`, clip→uint8, reverse rows for PNG top-down, then zlib-compress. Whole 1024² encode ≈ 0.3 s.
 - **MPFB's v2-skin node tree does not resolve to a simple base colour**, so a Cycles DIFFUSE bake returns black. Since the FBX export material replaces the node tree anyway, synthesize the diffuse directly (`make_diffuse`): warm skin body + a darker shorts-suggestive bottom band.
 - **A read-only `.umap` silently makes `save_map` return `False` with no error** (already recorded); re-hit in the review pipeline — `chmod u+w` the maps before rebuilding, otherwise the new character material never appears in shots.
+
+## 2026-11-07 — screenshot judge tool
+
+- `Tools/judge_screenshot.py` — runs an OpenRouter vision model over a screenshot vs an expected-scene description. Reads `OPENROUTER_API_KEY` from the repo `.env` (ignored). Base64 data-URI image under `image_url.url`; OpenAI-compatible body → `POST /api/v1/chat/completions`. `openai/gpt-4o-mini` returns a `{verdict, confidence, reason, missing}` JSON. It flags genuinely missing content (e.g. `main`'s pre-warm-skin character shot judged "no"); it is a pre-check, not the human verdict.
+- Test one: `Tools/judge_screenshot.py --image Screenshots/review-01-character.png --expect "<scene>" --verbose`. Bulk: `--shots` (parses the README rows).