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/RunTnBlockRegressionL75.py

@@ -0,0 +1,85 @@
+#!/usr/bin/env python3
+"""Keep the L74 false-solid TN lattice sample under a permanent block audit."""
+from __future__ import annotations
+
+import json
+import os
+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"
+BIN = ROOT / "Saved/Linux/l75/bin/VoxelForgeCoreHeadless-l75-clang"
+PROBE = (-80, -20, -3218)
+EXPECTED_DENSITY = 0.063384
+CAMERA_METERS = (19.266015625, -14.1001953125, -753.3740234375)
+REGRESSION = re.compile(r"\[L75TNBlockRegression\] (.*)")
+AUDIT = re.compile(r"\[UniformBlockProofAudit\] checked_blocks=(\d+) checked_samples=(\d+) "
+                   r"fallback_blocks=(\d+) unknown_blocks=(\d+) violations=(\d+)")
+PAIR = re.compile(r"([a-zA-Z0-9_]+)=([^ ]+)")
+
+
+def main() -> int:
+    if not DATA.is_file() or not BIN.is_file():
+        raise SystemExit("missing owner world or L75 Clang headless binary")
+    OUT.mkdir(parents=True, exist_ok=True)
+    camera = ",".join(f"{value:.12f}" for value in CAMERA_METERS) + ",0,0"
+    log = OUT / "tn-block-regression.log"
+    command = [
+        "taskset", "-c", "0-11", "prlimit", "--as=6442450944", "--", "timeout",
+        "1740s", str(BIN), str(DATA), "--world-assembler-prototype",
+        "--stream-benchmark", "--stream-pipeline", "--stream-hash-tiles",
+        "--audit-uniform-block-proofs", "--workers=8", "--clip-radius=3",
+        "--max-clip-level=8", "--max-level=8", f"--camera={camera}",
+    ]
+    environment = os.environ.copy()
+    environment["VOXELFORGE_L75_TN_BLOCK_REGRESSION"] = "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)
+    content = log.read_text(encoding="utf-8", errors="replace")
+    probes = []
+    for line in content.splitlines():
+        match = REGRESSION.search(line)
+        if match:
+            row = dict(PAIR.findall(match.group(1)))
+            row.update(density=float(row["density"]), proof_safe=int(row["proof_safe"]))
+            row["tile_origin"] = tuple(int(value) for value in
+                                       row["tile_origin"].strip("()").split(","))
+            probes.append(row)
+    audit_match = AUDIT.search(content)
+    if not probes or audit_match is None:
+        raise SystemExit(f"TN regression did not cover the target lattice sample; see {log}")
+    checked, samples, fallback, unknown, violations = map(int, audit_match.groups())
+    density_matches = all(abs(row["density"] - EXPECTED_DENSITY) <= 1.0e-6
+                          for row in probes)
+    false_solid_proofs = sum(row["proof_safe"] and row["verdict"] == "solid"
+                             for row in probes)
+    row = {
+        "probe": PROBE, "expected_density": EXPECTED_DENSITY,
+        "observed_densities": [probe["density"] for probe in probes],
+        "block_intervals": [{key: probe[key] for key in
+                              ("tile_origin", "step", "block", "verdict", "proof_safe", "unknown")}
+                             for probe in probes],
+        "checked_blocks": checked, "checked_samples": samples,
+        "fallback_blocks": fallback, "unknown_blocks": unknown,
+        "violations": violations, "false_solid_proofs": false_solid_proofs,
+        "exit_code": result.returncode,
+        "wall_s": round(time.monotonic() - started, 3),
+        "log": str(log.relative_to(ROOT)),
+    }
+    (OUT / "tn-block-regression.json").write_text(json.dumps(row, indent=2) + "\n",
+                                                   encoding="utf-8")
+    print("[L75TNRegression] " + json.dumps(row, sort_keys=True), flush=True)
+    if result.returncode != 0 or not density_matches or false_solid_proofs or violations:
+        raise SystemExit(f"TN block regression failed; see {log}")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())