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/RunAuditSweepL75.py

@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+"""Audit certified legacy density blocks across 20 deterministic camera positions per stratum."""
+from __future__ import annotations
+
+import json
+import re
+import statistics
+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"
+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),
+}
+OFFSETS = [(x, y) for y in (0.1, 4.1, 8.1, 12.1)
+           for x in (0.1, 4.1, 8.1, 12.1, 16.1)]
+AUDIT = re.compile(
+    r"\[UniformBlockProofAudit\] checked_blocks=(\d+) checked_samples=(\d+) "
+    r"fallback_blocks=(\d+) unknown_blocks=(\d+) violations=(\d+)"
+)
+TILE = re.compile(
+    r"\[WorldAssemblerTilePipeline\] .*?solid_boxes=(\d+) air_boxes=(\d+) "
+    r"mixed_boxes=(\d+) unknown_boxes=(\d+) whole_tile_skips=(\d+).*?"
+    r"classification_worker_ms=([0-9.]+)"
+)
+VIOLATION = re.compile(r"\[UniformBlockProofViolation\]")
+
+
+def run(view: int, position: int, offset: tuple[int, int]) -> dict:
+    base = CAMERAS[view]
+    camera = ",".join(f"{value:.12f}" for value in
+                       (base[0] + offset[0], base[1] + offset[1], base[2])) + ",0,0"
+    log = OUT / f"audit-s{view}-p{position:02d}.log"
+    command = [
+        "taskset", "-c", "0-11", "prlimit", "--as=6442450944", "--", "timeout",
+        "1740s", str(BIN), str(DATA), "--world-assembler-prototype", "--stream-benchmark",
+        "--stream-pipeline", "--workers=8", "--clip-radius=3",
+        "--max-clip-level=8", "--max-level=8", f"--camera={camera}",
+        "--audit-uniform-block-proofs", "--profile-lod-work",
+    ]
+    started = time.monotonic()
+    with log.open("w", encoding="utf-8") as output:
+        result = subprocess.run(command, cwd=ROOT, stdout=output, stderr=subprocess.STDOUT,
+                                check=False, timeout=1740)
+    content = log.read_text(encoding="utf-8", errors="replace")
+    audit = AUDIT.search(content)
+    tile = TILE.search(content)
+    if result.returncode != 0 or audit is None or tile is None:
+        raise SystemExit(f"audit run failed or summary is missing; see {log}")
+    checked, samples, fallback, unknown, violations = map(int, audit.groups())
+    solid, air, mixed, tile_unknown, tile_skips = map(int, tile.groups()[:5])
+    classifier_ms = float(tile.group(6))
+    violation_lines = len(VIOLATION.findall(content))
+    row = {
+        "strate": view, "position": position, "offset_m": list(offset),
+        "exit_code": result.returncode, "wall_s": round(time.monotonic() - started, 3),
+        "checked_blocks": checked, "checked_samples": samples,
+        "fallback_blocks": fallback, "unknown_blocks": unknown,
+        "violations": violations + violation_lines,
+        "block_proof_hit_pct": round(100.0 * checked / max(checked + fallback, 1), 2),
+        "tile_solid_boxes": solid, "tile_air_boxes": air, "tile_mixed_boxes": mixed,
+        "tile_unknown_boxes": tile_unknown, "tile_whole_skips": tile_skips,
+        "classification_worker_ms": classifier_ms,
+        "log": str(log.relative_to(ROOT)),
+    }
+    print("[L75AuditSweepRun] " + json.dumps(row, sort_keys=True), flush=True)
+    if row["violations"] != 0:
+        raise SystemExit(f"uniform block proof violation; see {log}")
+    return row
+
+
+def main() -> int:
+    OUT.mkdir(parents=True, exist_ok=True)
+    if not DATA.is_file() or not BIN.is_file():
+        raise SystemExit("missing owner world or L75 Clang headless binary")
+    rows = [run(view, index, offset) for view in range(4)
+            for index, offset in enumerate(OFFSETS)]
+    summary = []
+    for view in range(4):
+        group = [row for row in rows if row["strate"] == view]
+        checked = sum(row["checked_blocks"] for row in group)
+        fallback = sum(row["fallback_blocks"] for row in group)
+        costs = [row["classification_worker_ms"] for row in group]
+        summary.append({
+            "strate": view, "positions": len(group), "violations": sum(
+                row["violations"] for row in group), "checked_blocks": checked,
+            "fallback_blocks": fallback, "proof_hit_pct": round(
+                100.0 * checked / max(checked + fallback, 1), 2),
+            "classifier_ms_p50": round(statistics.median(costs), 3),
+            "classifier_ms_p95": round(sorted(costs)[int(0.95 * (len(costs) - 1))], 3),
+        })
+    if any(row["checked_blocks"] == 0 for row in summary):
+        raise SystemExit("block interval audit did not check a proof block for every strate")
+    result = {"runs": rows, "summary": summary}
+    (OUT / "audit-sweep.json").write_text(json.dumps(result, indent=2) + "\n",
+                                          encoding="utf-8")
+    for row in summary:
+        print("[L75AuditSweepSummary] " + json.dumps(row, sort_keys=True), flush=True)
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())