feat(review): Blender screenshots beside the in-game captures, with signoff

Two tools for the comparison the review was missing.

- Tools/blender_screenshots.py renders out of a .blend: one image per mesh object, and
  four turntable angles of the whole scene, framed from the scene's own bounds so adding
  geometry never silently crops a shot. Output lands in Screenshots/blender/, beside the
  in-game captures.
- Tools/build_comparison_md.py writes Screenshots/COMPARISON.md: a table with the in-game
  capture and its Blender render side by side per row, then a signoff table with one row
  per in-game screen. Unmatched shots show an em dash rather than disappearing, because a
  missing Blender render is information too.

The first run already earns its keep: the Blender render of the owner's hot hatch is red
with clear glazing, while the in-game capture of the same asset is near-black, so the
material colour is being lost on import - visible in one glance in the new page.

Tools/build_comparison_md.py

@@ -0,0 +1,159 @@
+#!/usr/bin/env python3
+"""Build the Blender-vs-in-game comparison page.
+
+    python3 Tools/build_comparison_md.py
+
+Reads every in-game capture in `Screenshots/demo/` and every Blender render in
+`Screenshots/blender/`, pairs them by name, and writes `Screenshots/COMPARISON.md`:
+
+* one table with the two images **side by side per row**, so a mismatch is visible in a
+  single glance rather than by opening two files;
+* one signoff table, one row per in-game screen, for the owner's verdict.
+
+Pairing is by name: `review-demo-vehicle.png` pairs with `vehicle-angle-*.png` because
+both mention `vehicle`; anything unmatched is shown with an em dash rather than being
+quietly dropped, since a missing Blender render is itself information.
+"""
+
+from __future__ import annotations
+
+import os
+import re
+
+DEMO_DIR = "Screenshots/demo"
+BLENDER_DIR = "Screenshots/blender"
+OUT = "Screenshots/COMPARISON.md"
+
+# Shots that are about a modelled asset pair with a Blender render; the street and
+# building shots have no Blender counterpart because those meshes come from the Geo
+# pipeline, not from a .blend.
+ASSET_KEYWORDS = ("vehicle",)
+
+# Shots are named after the camera, renders after the asset. Without this the character
+# shots never pair with the character renders, because "third-person-front" and
+# "character-angle-035" share no words.
+SHOT_ALIASES = {
+    "third-person": "character",
+    "third-person-front": "character",
+    "third-person-walk": "character",
+}
+
+
+def demo_shots():
+    if not os.path.isdir(DEMO_DIR):
+        return []
+    return sorted(f for f in os.listdir(DEMO_DIR) if f.endswith(".png"))
+
+
+def blender_renders():
+    if not os.path.isdir(BLENDER_DIR):
+        return []
+    return sorted(f for f in os.listdir(BLENDER_DIR) if f.endswith(".png"))
+
+
+def shot_label(filename):
+    name = os.path.splitext(filename)[0]
+    name = re.sub(r"^review-demo-", "", name)
+    return name.replace("-", " ")
+
+
+def best_blender_match(shot, renders):
+    """Pick the Blender render whose name shares the most words with the shot."""
+    stem = os.path.splitext(shot)[0].lower().replace("review-demo-", "")
+    words = set(re.split(r"[-_]", stem))
+    for alias, asset in SHOT_ALIASES.items():
+        if alias in stem:
+            words.add(asset)
+    scored = []
+    for render in renders:
+        render_words = set(re.split(r"[-_]", os.path.splitext(render)[0].lower()))
+        score = len(words & render_words)
+        if score:
+            scored.append((score, render))
+    if not scored:
+        return None
+    scored.sort(key=lambda item: (-item[0], item[1]))
+    return scored[0][1]
+
+
+def relative_to_page(path):
+    """Paths in the page are relative to Screenshots/, where COMPARISON.md lives."""
+    if not path:
+        return path
+    base = os.path.dirname(OUT)
+    return os.path.relpath(path, base).replace(os.sep, "/")
+
+
+def image_cell(path, width=520):
+    if not path:
+        return "—"
+    return f'<img src="{relative_to_page(path)}" width="{width}">'
+
+
+def build():
+    shots = demo_shots()
+    renders = blender_renders()
+    lines = [
+        "# Blender vs in-game",
+        "",
+        "Generated by `Tools/build_comparison_md.py` — do not edit by hand.",
+        "",
+        f"- In-game captures: `{DEMO_DIR}/` ({len(shots)} files)",
+        f"- Blender renders: `{BLENDER_DIR}/` ({len(renders)} files), made by `Tools/blender_screenshots.py`",
+        "",
+        "Left is what the engine draws, right is what Blender has. A gap between them is the",
+        "import problem, not a taste problem: scale, material colour, missing parts and split",
+        "systems all show up here before they show up in a review.",
+        "",
+        "## Side by side",
+        "",
+        "| In-game | Blender | Shot |",
+        "| --- | --- | --- |",
+    ]
+
+    paired = {}
+    for shot in shots:
+        match = best_blender_match(shot, renders)
+        paired[shot] = match
+        lines.append(
+            f"| {image_cell(f'{DEMO_DIR}/{shot}')} "
+            f"| {image_cell(f'{BLENDER_DIR}/{match}' if match else None)} "
+            f"| `{shot}` |")
+    if not shots:
+        lines.append("| — | — | no captures |")
+
+    matched = sum(1 for v in paired.values() if v)
+    lines += [
+        "",
+        f"{matched} of {len(shots)} in-game captures have a Blender counterpart; the rest are",
+        "street and building shots whose meshes come from the Geo pipeline rather than a .blend.",
+        "",
+        "## Signoff",
+        "",
+        "One row per in-game screen. `—` in Blender means there is nothing to compare against.",
+        "",
+        "| # | In-game screen | Blender counterpart | Verdict | Notes |",
+        "| --- | --- | --- | --- | --- |",
+    ]
+    for index, shot in enumerate(shots, start=1):
+        match = paired[shot]
+        lines.append(
+            f"| {index} | `{shot}` | {f'`{match}`' if match else '—'} | ☐ | |")
+    if not shots:
+        lines.append("| — | — | — | ☐ | no captures |")
+
+    lines += [
+        "",
+        "Verdicts: ☐ pending · ☑ approved · ☒ rejected. The authoritative per-shot review stays",
+        "in [README.md](README.md); this page exists to compare Blender against the engine.",
+        "",
+    ]
+    os.makedirs(os.path.dirname(OUT) or ".", exist_ok=True)
+    with open(OUT, "w") as handle:
+        handle.write("\n".join(lines))
+    print(f"wrote {OUT} ({len(shots)} shots, {matched} paired, {len(renders)} renders)")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(build())