wip(assembler): round L37 -- FI mouth carve-fade fix, no raised bridge (style 0); research R1

The passage mouth fade multiplied the signed carve distance by zero, which turned native rock into an
open surface (the reason earlier rounds stamped walk pads at mouths); it now blends between the
uncarved field and the full signed carve. The FI style-0 route followed a lifted grade envelope over
the crater (the "bridge"); it now runs on the rim and follows the native surface. New built-shape and
crease audits with thresholds frozen before the fix (L36 and box controls fail). 24/24 passage rows,
30/30 determinism, 16/16 invariants, 18/18 interface/ring. Unreal: one recipe setter (uncompiled).
Research R1 (read-only, web): ranked proposals for natural walkable mouths, floor-limited carve first.

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

Standalone/Research/WorldAssemblerM3/Linux37/CaptureMouthOverviewL37.py

@@ -0,0 +1,80 @@
+#!/usr/bin/env python3
+"""Render the fixed 17 m FI mouth overview as a small JPEG."""
+import math
+import os
+import subprocess
+import time
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[4]
+OUT = Path(os.environ.get("VOXELFORGE_L37_OUT", ROOT / "Saved/Linux/l37"))
+CAPTURES = Path(os.environ.get("VOXELFORGE_L37_CAPTURE_DIR",
+                               Path(__file__).resolve().parent / "captures"))
+MESH = Path(os.environ.get("VOXELFORGE_L37_MESH",
+                           OUT / "owner-fi-ground-mouth.vfmesh"))
+RENDERER = Path(os.environ.get("VOXELFORGE_L37_RENDERER",
+    OUT / "bin/VoxelForgeOffscreenCapture-l37-final-clang"))
+PNG = OUT / "capture-png/owner-fi-ground-mouth-overview.png"
+JPEG = CAPTURES / "owner-fi-ground-mouth-overview.jpg"
+MOUTH = (5.600, 0.445, -55.156)
+CAMERA = (MOUTH[0] - 9.75, MOUTH[1] - 11.4, MOUTH[2] + 8.0)
+TARGET = (6.298233, 1.137233, -55.468264)
+FOV = 80.0
+
+
+def normalize(vector):
+    magnitude = math.sqrt(sum(value * value for value in vector))
+    return tuple(value / magnitude for value in vector)
+
+
+def camera_angles(camera, target):
+    delta = tuple(target[i] - camera[i] for i in range(3))
+    horizontal = math.hypot(delta[0], delta[1])
+    return math.degrees(math.atan2(delta[0], delta[1])), math.degrees(
+        math.atan2(delta[2], horizontal))
+
+
+def fmt(values):
+    return ",".join(f"{value:.6f}" for value in values)
+
+
+def run(name, command):
+    log = OUT / f"capture-overview-{name}.log"
+    wrapped = ["taskset", "-c", "0-11", "prlimit", "--as=6442450944", "--",
+               "timeout", "1800s", *map(str, command)]
+    started = time.monotonic()
+    with log.open("w", encoding="utf-8") as stream:
+        result = subprocess.run(wrapped, cwd=ROOT, stdout=stream,
+            stderr=subprocess.STDOUT, timeout=1800, check=False)
+    elapsed = time.monotonic() - started
+    print(f"[L37OverviewCaptureRun] step={name} elapsed={elapsed:.1f}s "
+          f"exit={result.returncode} log={log}", flush=True)
+    if result.returncode != 0:
+        raise SystemExit(f"{name} failed; see {log}")
+
+
+def main():
+    if not MESH.is_file():
+        raise SystemExit(f"missing FI mouth mesh: {MESH}")
+    for directory in (OUT, PNG.parent, CAPTURES):
+        directory.mkdir(parents=True, exist_ok=True)
+    yaw, pitch = camera_angles(CAMERA, TARGET)
+    run("render", [RENDERER, MESH, PNG, "--size=1600x900", f"--fov-deg={FOV}",
+        f"--camera-m={fmt(CAMERA)}", f"--yaw-deg={yaw:.6f}",
+        f"--pitch-deg={pitch:.6f}", "--tile-skirts=off", "--shade=readable",
+        "--headlamp=on", "--height-tint=on",
+        f"--height-center-m={TARGET[2]:.6f}", "--height-range-m=8",
+        "--tile-edges=off", f"--focus-region={fmt((*MOUTH, 20.0))}"])
+    run("jpeg", ["ffmpeg", "-nostdin", "-hide_banner", "-loglevel", "error",
+        "-y", "-i", PNG, "-frames:v", "1", "-q:v", "4", JPEG])
+    size = JPEG.stat().st_size if JPEG.exists() else 0
+    distance = math.dist(CAMERA, MOUTH)
+    print(f"[L37OverviewCapture] file={JPEG.relative_to(ROOT)} camera_to_mouth_m="
+          f"{distance:.3f} camera_m=({fmt(CAMERA)}) target_m=({fmt(TARGET)}) "
+          f"fov_deg={FOV:.1f} resolution=1600x900 bytes={size} "
+          f"status={'PASS' if 0 < size <= 300_000 else 'FAIL'}", flush=True)
+    raise SystemExit(0 if 0 < size <= 300_000 else 1)
+
+
+if __name__ == "__main__":
+    main()