tools(verify): fast/medium/full verification tiers with a compiled-in source stamp (L39); research R6

BuildLinux.sh hashes a sorted manifest of compiled inputs into VOXELFORGE_SOURCE_STAMP, printed first by
every executable; Standalone/Tools/verify/verify.py checks it before and after each tier and records
binary/input hashes and the resolved recipe, style map and layout. Fast (163 s) runs on the canonical owner
world only and asserts FI Style 2 / SW Style 1; medium (8 min) and full (26 min) add the style matrix,
GCC, determinism and cost. Controls: stale source, mislabelled style-0 owner, all-black capture, L30/L31,
L35/L36 and the L38 step are all rejected. No geometry change; owner hashes identical to L37.
Research R6: leak table, generator contract and a 10-step metre-native migration plan.

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

Standalone/Source/SourceStamp.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <cstdio>
+
+#ifndef VOXELFORGE_SOURCE_STAMP
+#define VOXELFORGE_SOURCE_STAMP "UNSTAMPED"
+#endif
+
+inline void VoxelForgePrintSourceStamp() noexcept
+{
+    std::printf("[VoxelForgeSourceStamp] sha256=%s\n", VOXELFORGE_SOURCE_STAMP);
+    std::fflush(stdout);
+}