research: cave planner merge evidence (L150, measurement only)

Merges cleanly. UE start: S1 -9%, S3 +11%, S0/S2 ~+1%. 30 m/s: near coverage 44.2 -> 38.5%, far holes +0.06 pp, p99
+2%. L80 near-ready slower in 6/8 cells (up to +7.9%), whole view faster in 7/8. Sweeps 15/16 each (seed 2).
Source/: VoxelForgeCoreAdapter.cpp.

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

Standalone/Research/WorldAssemblerM3/Linux150/RunL150SeedSweep.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+"""Run L147 composed gates on the actual L150 planner HEAD build."""
+from __future__ import annotations
+
+import importlib.util
+from pathlib import Path
+import sys
+
+
+ROOT = Path(__file__).resolve().parents[4]
+SOURCE = ROOT / "Standalone/Research/WorldAssemblerM3/Linux147/RunL147SeedSweep.py"
+spec = importlib.util.spec_from_file_location("l147_seed_sweep", SOURCE)
+if spec is None or spec.loader is None:
+    raise SystemExit("cannot load the L147 composed gate runner")
+runner = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(runner)
+runner.OUT = ROOT / "Saved/Linux/l150/seeds"
+runner.BIN = ROOT / "Standalone/bin/linux/VoxelForgeCoreHeadless-l150-head-clang"
+runner.STAMP = "c6b8a100355e271ddc40eb5973569d2ff4e2ba8d9c628c72f8e0af2493f0609f"
+
+
+if __name__ == "__main__":
+    raise SystemExit(runner.main())