passages: smoothed open-air shell joins (L110, v257) - partial, not merged

Bands = end profiles of per-control-span shell capsules (~9.35 m pitch = span spacing).
Shell now smooth-unions adjacent spans over 6 m and reuses the interior chord distance; a 0.60 m
clearance fades in 5-20 m from each mouth. Close-ups: bands reduced but still visible on part of
the exposed shell. Cost vs L109: near-ready +8..+12% (FI 0.88 -> 1.00, TN 0.92 -> 1.01 s @W12).
Audits, Clang/GCC determinism, fast tier and Linux UE build pass. Kept on its own branch.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Standalone/Research/WorldAssemblerM3/Linux110/VerifyL110Captures.py

@@ -0,0 +1,88 @@
+#!/usr/bin/env python3
+"""Check the paired L109/L110 capture set and 4 m shell close-ups."""
+from __future__ import annotations
+
+import hashlib
+import json
+from collections import Counter
+from pathlib import Path
+import struct
+
+
+ROOT = Path(__file__).resolve().parents[4]
+CAPTURE_ROOT = Path(__file__).resolve().parent / "captures"
+RESEARCH_ROOT = CAPTURE_ROOT.parent
+INDEX = CAPTURE_ROOT / "capture-index.json"
+OUTPUT = CAPTURE_ROOT / "capture-verification.json"
+
+
+def sha256(path: Path) -> str:
+    digest = hashlib.sha256()
+    with path.open("rb") as stream:
+        for block in iter(lambda: stream.read(1024 * 1024), b""):
+            digest.update(block)
+    return digest.hexdigest()
+
+
+def png_size(path: Path) -> tuple[int, int]:
+    with path.open("rb") as stream:
+        header = stream.read(24)
+    if len(header) != 24 or header[:8] != b"\x89PNG\r\n\x1a\n" or header[12:16] != b"IHDR":
+        raise RuntimeError(f"invalid PNG: {path}")
+    return struct.unpack(">II", header[16:24])
+
+
+def main() -> int:
+    captures = json.loads(INDEX.read_text(encoding="utf-8"))["captures"]
+    counts = {variant: Counter(row["kind"] for row in captures
+                               if row["variant"] == variant)
+              for variant in ("before", "after")}
+    by_variant = {variant: {row["name"]: row for row in captures
+                            if row["variant"] == variant}
+                  for variant in ("before", "after")}
+    errors: list[str] = []
+    for variant in ("before", "after"):
+        rows = [row for row in captures if row["variant"] == variant]
+        if len(rows) != 53:
+            errors.append(f"{variant}: expected 53 captures, got {len(rows)}")
+        for row in rows:
+            image = RESEARCH_ROOT / row["capture"]
+            if not row.get("verified") or row.get("render_tile_skirts") != "off":
+                errors.append(f"{variant}/{row['name']}: render verification flags failed")
+            if row.get("drawn_triangles", 0) <= 0 or not image.is_file():
+                errors.append(f"{variant}/{row['name']}: missing geometry or image")
+            elif png_size(image) != (1920, 1080):
+                errors.append(f"{variant}/{row['name']}: unexpected image size {png_size(image)}")
+        closeups = [row for row in rows if row["kind"] == "open-air-closeup"]
+        if len(closeups) != 11:
+            errors.append(f"{variant}: expected 11 close-ups, got {len(closeups)}")
+        for row in closeups:
+            distance = row.get("shell_standoff_actual_m")
+            if distance is None or not 3.0 <= distance <= 5.0:
+                errors.append(f"{variant}/{row['name']}: close-up standoff {distance}")
+    names_before, names_after = set(by_variant["before"]), set(by_variant["after"])
+    if names_before != names_after:
+        errors.append("before/after capture names do not match")
+    pair_counts = Counter()
+    for name in sorted(names_before & names_after):
+        left, right = by_variant["before"][name], by_variant["after"][name]
+        same = sha256(RESEARCH_ROOT / left["capture"]) == sha256(
+            RESEARCH_ROOT / right["capture"])
+        pair_counts[f"{left['kind']}_{'identical' if same else 'changed'}"] += 1
+    summary = {
+        "status": "PASS" if not errors else "FAIL",
+        "capture_count": len(captures),
+        "open_air_sections": len(json.loads(INDEX.read_text(encoding="utf-8"))[
+            "open_air_sections"]),
+        "per_variant_kind_counts": {variant: dict(sorted(counts[variant].items()))
+                                     for variant in counts},
+        "paired_image_bytes": dict(sorted(pair_counts.items())),
+        "errors": errors,
+    }
+    OUTPUT.write_text(json.dumps(summary, indent=2) + "\n", encoding="utf-8")
+    print(json.dumps(summary, sort_keys=True))
+    return 0 if not errors else 1
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())