passages: prepared per-segment data + per-column XY projection cache (L98, exact)

Per-world prepared chord/length/radius/Catmull-Rom/floor-profile data (310 segments, ~66 KB,
<0.04 ms); same expression grouping, divisions and square roots, so output is bit-identical
(zero density/tile mismatches, Clang vs GCC equal). No measurable readiness gain - the cost is
the number of samples running passage work, not per-sample arithmetic. Note: the report's
world labels are shifted by one row (the 2,850-tile row is SurfaceWorld). Fast tier PASS;
Linux UE host builds.

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

Standalone/Research/WorldAssemblerM3/Linux98/RunL98Census.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+"""Three interleaved L77 passage-share censuses for pre-L98 and L98 Core."""
+from __future__ import annotations
+
+import json
+import re
+import subprocess
+import time
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[4]
+OUT = ROOT / "Saved/Linux/l98/census"
+DATA = ROOT / "Standalone/data/owner_world.json"
+BINARIES = {
+    "pre": ROOT / "Saved/Linux/l98/profile-pre-bin/VoxelForgeCoreHeadless-l98-pre-profile",
+    "post": ROOT / "Saved/Linux/l98/profile-post-bin/VoxelForgeCoreHeadless-l98-post-profile",
+}
+CAMERAS = {
+    "FI": (25.8369140625, 3.19921875, -737.0),
+    "TN": (19.166015625, -14.2001953125, -753.3740234375),
+}
+SAMPLE = re.compile(r"^\[L77Sample\] pc=(0x\w+) lod=(\d+) .*?phase=(\S+) .*?weight=(\d+)$", re.M)
+SAMPLER = re.compile(r"^\[L77Sampler\] action=stop .*?samples=(\d+).*?status=PASS$", re.M)
+
+
+def run(world: str, label: str, rep: int) -> dict:
+    OUT.mkdir(parents=True, exist_ok=True)
+    log = OUT / f"{label}-{world.lower()}-r{rep}.log"
+    camera = ",".join(f"{value:.12f}" for value in CAMERAS[world]) + ",0,0"
+    command = [
+        "taskset", "-c", "0-11", "prlimit", "--as=6442450944", "--",
+        "env", "timeout", "1740s", str(BINARIES[label]), str(DATA),
+        "--world-assembler-prototype", "--stream-benchmark", "--stream-pipeline",
+        "--workers=8", "--clip-radius=3", "--max-clip-level=8", "--max-level=8",
+        f"--camera={camera}", "--profile-lod-work", "--linux77-profile",
+    ]
+    start = time.monotonic()
+    with log.open("w", encoding="utf-8") as stream:
+        result = subprocess.run(command, cwd=ROOT, stdout=stream,
+                                stderr=subprocess.STDOUT, check=False, timeout=1740)
+    output = log.read_text(encoding="utf-8", errors="replace")
+    samples = [(int(lod), phase, int(weight))
+               for _pc, lod, phase, weight in SAMPLE.findall(output)]
+    sampler = SAMPLER.search(output)
+    if result.returncode or not samples or sampler is None:
+        raise RuntimeError(f"census failed: exit={result.returncode} {log}")
+    near = [row for row in samples if row[0] <= 2]
+    passage = sum(weight for _, phase, weight in near if phase == "passages")
+    total = sum(weight for _, _, weight in near)
+    row = {
+        "world": world, "binary": label, "replicate": rep,
+        "exit_code": result.returncode, "wall_s": round(time.monotonic() - start, 3),
+        "sampler_samples": int(sampler.group(1)), "near_lod_samples": len(near),
+        "near_lod_weighted_ticks": total,
+        "near_lod_passage_weighted_ticks": passage,
+        "near_lod_passage_share_pct": 100.0 * passage / total,
+        "log": str(log.relative_to(ROOT)),
+    }
+    print("[L98CensusRun] " + json.dumps(row, sort_keys=True), flush=True)
+    return row
+
+
+def main() -> int:
+    for binary in (*BINARIES.values(), DATA):
+        if not binary.is_file():
+            raise SystemExit(f"missing input: {binary}")
+    rows = []
+    orders = (("pre", "post"), ("post", "pre"), ("pre", "post"))
+    for rep, order in enumerate(orders, 1):
+        for label in order:
+            for world in CAMERAS:
+                rows.append(run(world, label, rep))
+                (OUT / "runs-partial.json").write_text(json.dumps(rows, indent=2) + "\n",
+                                                       encoding="utf-8")
+    summary = {}
+    for world in CAMERAS:
+        summary[world] = {}
+        for label in BINARIES:
+            values = [row["near_lod_passage_share_pct"] for row in rows
+                      if row["world"] == world and row["binary"] == label]
+            summary[world][label] = {
+                "runs_pct": values, "mean_pct": sum(values) / len(values),
+            }
+    (OUT / "summary.json").write_text(json.dumps(
+        {"runs": rows, "near_lod_passage_share": summary}, indent=2) + "\n",
+        encoding="utf-8")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())