skip: passage proof bounds include wall/floor relief (L75 soundness fix); FI -7.6%

L74's passage bound omitted the 0.21 m wall relief and 0.20 m floor relief, so its whole-tile
proof was unsound in principle (no tested view hit it). Passage support is now bounded per route
segment by four parameter-subinterval boxes using Catmull-Rom derivative extrema, local max
radius and relief padding. Stratum slicing only at LOD0-2 in FI/VS. Legacy sub-tile block
certificates are audit-only (runtime version was slower). TN regression (-80,-20,-3218) kept.

Exact full-grid vs skip hashes on every tile, 4 views, Clang/GCC, W1/W8/W12; control caught;
80-camera sweep 0 violations. Whole view vs c67b200: SW -1.3%, FI -7.6%, TN -2.3%, VS +0.2%.
Compiles in the Linux UE host (VFHostEditor, 27/27 actions).

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

Standalone/Research/WorldAssemblerM3/Linux75/FalsifierL75.py

@@ -0,0 +1,171 @@
+#!/usr/bin/env python3
+"""Compare full-grid and proof-skip mesh hashes for all four owner arrivals."""
+from __future__ import annotations
+
+import argparse
+import json
+import re
+import subprocess
+import time
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[4]
+OUT = ROOT / "Saved/Linux/l75/logs"
+DATA = ROOT / "Standalone/data/owner_world.json"
+BINS = {
+    "clang": ROOT / "Saved/Linux/l75/bin/VoxelForgeCoreHeadless-l75-clang",
+    "gcc": ROOT / "Saved/Linux/l75/bin-gcc/VoxelForgeCoreHeadless-l75-gcc",
+}
+CAMERAS = {
+    0: (8.0, 16.0, -372.2626953125),
+    1: (25.8369140625, 3.19921875, -737.0),
+    2: (19.166015625, -14.2001953125, -753.3740234375),
+    3: (-20.0625, -5.068359375, -900.353515625),
+}
+HASH_ROW = re.compile(
+    r"\[PipelineTileHash\] lod=(\d+) x=(-?\d+) y=(-?\d+) z=(-?\d+) "
+    r"density=(0x[0-9a-fA-F]+) mesh=(0x[0-9a-fA-F]+) "
+    r"payload=(0x[0-9a-fA-F]+) topology=(0x[0-9a-fA-F]+)"
+)
+EMPTY_DENSITY_HASH = "0xcbf29ce484222325"
+
+
+def read_hashes(path: Path) -> tuple[dict, set[tuple[int, int, int, int]]]:
+    hashes = {}
+    generated_density = set()
+    for line in path.read_text(encoding="utf-8", errors="replace").splitlines():
+        row = HASH_ROW.search(line)
+        if row:
+            lod, x, y, z = (int(row.group(i)) for i in range(1, 5))
+            hashes[(lod, x, y, z)] = {
+                "density": row.group(5).lower(), "mesh": row.group(6).lower(),
+                "payload": row.group(7).lower(), "topology": row.group(8).lower(),
+            }
+            if row.group(5).lower() != EMPTY_DENSITY_HASH:
+                generated_density.add((lod, x, y, z))
+    return hashes, generated_density
+
+
+def run(compiler: str, view: int, workers: int, allow_skips: bool,
+        negative_control: bool = False) -> Path:
+    camera = ",".join(f"{value:.12f}" for value in CAMERAS[view]) + ",0,0"
+    mode = "negative" if negative_control else "skip" if allow_skips else "reference"
+    log = OUT / f"{mode}-{compiler}-view{view}-w{workers}.log"
+    command = [
+        "taskset", "-c", "0-11", "prlimit", "--as=6442450944", "--",
+        "timeout", "1740s", str(BINS[compiler]), str(DATA),
+        "--world-assembler-prototype", "--stream-benchmark", "--stream-pipeline",
+        "--force-generate", f"--workers={workers}", "--clip-radius=3",
+        "--max-clip-level=8", "--max-level=8", f"--camera={camera}",
+        "--stream-hash-tiles-allow-skips" if allow_skips or negative_control
+        else "--stream-hash-tiles",
+    ]
+    import os
+    environment = os.environ.copy()
+    if negative_control:
+        environment["VOXELFORGE_L74_TIGHT_PROOF_CONTROL"] = "1"
+    started = time.monotonic()
+    with log.open("w", encoding="utf-8") as output:
+        result = subprocess.run(command, cwd=ROOT, env=environment, stdout=output,
+                                stderr=subprocess.STDOUT, check=False, timeout=1740)
+    hashes, _ = read_hashes(log)
+    print(json.dumps({"compiler": compiler, "view": view, "workers": workers,
+                      "mode": mode, "exit_code": result.returncode,
+                      "hash_rows": len(hashes), "wall_s": round(time.monotonic()-started, 3),
+                      "log": str(log.relative_to(ROOT))}, sort_keys=True), flush=True)
+    if result.returncode != 0 or not hashes:
+        raise SystemExit(f"hash generation failed; see {log}")
+    return log
+
+
+def compare(reference: Path, candidate: Path) -> dict:
+    reference_hashes, _ = read_hashes(reference)
+    candidate_hashes, candidate_generated = read_hashes(candidate)
+    missing = sorted(reference_hashes.keys() - candidate_hashes.keys())
+    extra = sorted(candidate_hashes.keys() - reference_hashes.keys())
+    mismatch_counts = {field: 0 for field in ("mesh", "payload", "topology", "density_processed")}
+    mismatch_examples = []
+    for key in sorted(reference_hashes.keys() & candidate_hashes.keys()):
+        a, b = reference_hashes[key], candidate_hashes[key]
+        fields = ["mesh", "payload", "topology"]
+        if key in candidate_generated:
+            fields.append("density")
+        for field in fields:
+            if a[field] != b[field]:
+                label = "density_processed" if field == "density" else field
+                mismatch_counts[label] += 1
+                if len(mismatch_examples) < 8:
+                    mismatch_examples.append({"key": key, "field": field,
+                                              "reference": a[field], "candidate": b[field]})
+    return {"reference": str(reference.relative_to(ROOT)),
+            "candidate": str(candidate.relative_to(ROOT)),
+            "reference_tiles": len(reference_hashes), "candidate_tiles": len(candidate_hashes),
+            "missing_keys": missing[:8], "missing_key_count": len(missing),
+            "extra_keys": extra[:8], "extra_key_count": len(extra),
+            "mismatch_counts": mismatch_counts, "mismatch_examples": mismatch_examples,
+            "mesh_topology_equal": not missing and not extra
+                and mismatch_counts["mesh"] == 0 and mismatch_counts["topology"] == 0}
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--phase", choices=("matrix", "workers", "negative"), required=True)
+    args = parser.parse_args()
+    OUT.mkdir(parents=True, exist_ok=True)
+    missing = [str(path) for path in [DATA, *BINS.values()] if not path.is_file()]
+    if missing:
+        raise SystemExit("missing input: " + ", ".join(missing))
+    comparisons = []
+    if args.phase == "matrix":
+        references = {}
+        skip_eight = {}
+        for compiler in ("clang", "gcc"):
+            for view in range(4):
+                reference = run(compiler, view, 8, False)
+                skip = run(compiler, view, 8, True)
+                references[(compiler, view)] = reference
+                skip_eight[(compiler, view)] = skip
+                comparisons.append(compare(reference, skip))
+        for view in range(4):
+            comparisons.append(compare(references[("clang", view)],
+                                      references[("gcc", view)]))
+            comparisons.append(compare(skip_eight[("clang", view)],
+                                      skip_eight[("gcc", view)]))
+        (OUT / "falsifier-matrix.json").write_text(json.dumps(comparisons, indent=2)+"\n",
+                                                    encoding="utf-8")
+    elif args.phase == "workers":
+        for compiler in ("clang", "gcc"):
+            for view in range(4):
+                reference = OUT / f"reference-{compiler}-view{view}-w8.log"
+                if not reference.is_file():
+                    raise SystemExit(f"missing reference from matrix phase: {reference}")
+                baseline = OUT / f"skip-{compiler}-view{view}-w8.log"
+                for workers in (1, 12):
+                    candidate = run(compiler, view, workers, True)
+                    comparisons.append(compare(reference, candidate))
+                    comparisons.append(compare(baseline, candidate))
+        (OUT / "falsifier-workers.json").write_text(json.dumps(comparisons, indent=2)+"\n",
+                                                     encoding="utf-8")
+    else:
+        for view in range(4):
+            reference = OUT / f"reference-clang-view{view}-w8.log"
+            candidate = run("clang", view, 8, True, negative_control=True)
+            comparisons.append(compare(reference, candidate))
+        (OUT / "falsifier-negative-control.json").write_text(
+            json.dumps(comparisons, indent=2)+"\n", encoding="utf-8")
+        caught = any(not row["mesh_topology_equal"] for row in comparisons)
+        print(f"[L74NegativeControlResult] caught={int(caught)}", flush=True)
+        if not caught:
+            return 2
+        return 0
+    failures = [row for row in comparisons if not row["mesh_topology_equal"]
+                or row["missing_key_count"] or row["extra_key_count"]
+                or any(row["mismatch_counts"].values())]
+    print(f"[L74Falsifier] phase={args.phase} comparisons={len(comparisons)} "
+          f"mesh_topology_failures={len(failures)}", flush=True)
+    return 0 if not failures else 1
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())