wip(assembler): round L19 -- strate ceilings closed at every LOD; ledges diagnosed

The shared boundary-cap path now emits a cap wherever the field is solid just below a strate's
configured top (it previously required a solid-to-air crossing there) and checks a 5x5 perimeter
grid before suppressing a fallback cap. Strict audit: 0 misses / 0 edge gaps, LOD0-8.
farHorizonVersion 3 -> 4. SurfaceWorld LOD0-2, full detail and exact queries unchanged; 28/28
matrix plus 14/14 crossing; route parity and proofs pass.
Ledges: the lower stratum's terrain at the FI/SW interface, seen through the FI void, sampled at
0.5/1/2 m at LOD1-3 (up to 1.5 m / 7.7 m ring steps). Fix deferred to the units/layers round.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CSFYgsdW8ejZSyiMf4qRSX

Standalone/Research/WorldAssemblerM3/Linux19/CaptureLinux19.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+"""Render matched L19 review captures from the L18 and L19 scene exports."""
+import os
+import subprocess
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[4]
+CAPTURE = ROOT / "Standalone/bin/linux/VoxelForgeOffscreenCapture-linux19-clang"
+BEFORE = ROOT / "Standalone/Research/WorldAssemblerM3/Linux18/exports"
+AFTER = ROOT / "Saved/Linux/l19-diagnostics"
+OUT = ROOT / "Standalone/Research/WorldAssemblerM3/Linux19/captures"
+PNG_OUT = ROOT / "Saved/Linux/l19-captures-temp"
+LOGS = ROOT / "Saved/Linux/l19-diagnostics"
+OUT.mkdir(parents=True, exist_ok=True)
+PNG_OUT.mkdir(parents=True, exist_ok=True)
+env = os.environ.copy()
+env["LP_NUM_THREADS"] = "12"
+env["XDG_CACHE_HOME"] = str(ROOT / "Saved/Linux/mesa-cache")
+
+views = [
+    ("floating-islands-flat-square-before", BEFORE / "floating-islands-flat-square.vfmesh",
+     (-11.612444, -118.221237, -19.8452), 0, 0, True),
+    ("floating-islands-flat-square-after", AFTER / "floating-islands-flat-square-after.vfmesh",
+     (-11.612444, -118.221237, -19.8452), 0, 0, True),
+    ("floating-islands-owner-angle-before", BEFORE / "floating-islands-island-view.vfmesh",
+     (-22, -19, -22.8), 0, -4, True),
+    ("floating-islands-owner-angle-after", AFTER / "floating-islands-island-view-after.vfmesh",
+     (-22, -19, -22.8), 0, -4, True),
+    ("floating-islands-owner-ground-before", AFTER / "floating-islands-owner-ground-before.vfmesh",
+     (-6.3, -19.06, -21.0), 0, -4, True),
+    ("floating-islands-owner-ground-after", AFTER / "floating-islands-owner-ground-after.vfmesh",
+     (-6.3, -19.06, -21.0), 0, -4, True),
+    ("floating-islands-ceiling-up-after", AFTER / "floating-islands-island-view-after.vfmesh",
+     (-22, -19, -22.8), 0, 80, True),
+    ("surface-world-l1-spawn-before", BEFORE / "surface-world-l1-spawn.vfmesh",
+     (0, -35, -487.94), 0, -22, False),
+    ("surface-world-l1-spawn-after", AFTER / "surface-world-l1-spawn-after.vfmesh",
+     (0, -35, -487.94), 0, -22, False),
+    ("surface-world-horizon-before", BEFORE / "surface-world-l1-spawn.vfmesh",
+     (0, -35, -487.94), 0, 0, False),
+    ("surface-world-horizon-after", AFTER / "surface-world-l1-spawn-after.vfmesh",
+     (0, -35, -487.94), 0, 0, False),
+    ("surface-world-rings-above-before", BEFORE / "surface-world-l1-spawn.vfmesh",
+     (0, -35, -280), 0, -90, True),
+    ("surface-world-rings-above-after", AFTER / "surface-world-l1-spawn-after.vfmesh",
+     (0, -35, -280), 0, -90, True),
+]
+
+for name, scene, camera, yaw, pitch, tile_edges in views:
+    if not scene.exists():
+        raise SystemExit(f"missing scene: {scene}")
+    png = PNG_OUT / f"{name}.png"
+    jpg = OUT / f"{name}.jpg"
+    render_log = LOGS / f"{name}-render.log"
+    convert_log = LOGS / f"{name}-jpeg.log"
+    command = [str(CAPTURE), str(scene), str(png), "--size=1600x900",
+        "--shade=readable", f"--tile-edges={'on' if tile_edges else 'off'}",
+        "--tile-edge-width-m=0.15", "--camera-m="+",".join(map(str, camera)),
+        f"--yaw-deg={yaw}", f"--pitch-deg={pitch}"]
+    with render_log.open("w", encoding="utf-8") as stream:
+        subprocess.run(command, cwd=ROOT, env=env, stdout=stream,
+                       stderr=subprocess.STDOUT, check=True)
+    ffmpeg = ["ffmpeg", "-nostdin", "-hide_banner", "-loglevel", "error", "-y",
+        "-i", str(png), "-frames:v", "1", "-q:v", "4", str(jpg)]
+    with convert_log.open("w", encoding="utf-8") as stream:
+        subprocess.run(ffmpeg, cwd=ROOT, env=env, stdout=stream,
+                       stderr=subprocess.STDOUT, check=True)
+    if jpg.stat().st_size > 300_000:
+        raise SystemExit(f"{jpg.name} exceeds the 300 KB review limit")
+    print(f"[Capture] {jpg.relative_to(ROOT)} bytes={jpg.stat().st_size} status=PASS", flush=True)