feat(composer): PROMOTION -- the corpus grows itself, and it did not collapse

Tier 5. §3.3's answer to Jahni's "I'd like the system to not rely at all on
the handmade ones": promotion does not REMOVE the authored seed, it dilutes
it. Every invented strate that measures well rejoins the corpus.

Five simulated seasons, 24 candidates each:

  season  corpus  project/default/promoted  survival  spread
    1       15          4/8/3               20.8%     0.869
    2       20          4/8/8               54.2%     0.849
    3       20          4/8/8               54.2%     0.849
    4       21          4/8/9               45.8%     0.916
    5       21          4/8/9               50.0%     0.916

Corpus 12 -> 21, of which 9 are discovered. Survival roughly doubles.

⭐ AND THE COLLAPSE RISK DID NOT MATERIALISE, which was the thing worth
measuring rather than assuming. Promotion selects survivors, and blending
survivors repeatedly can converge the corpus onto a narrow safe region --
the composer would get better at passing and worse at surprising. Spread
went 0.869 -> 0.916. It dipped and plateaued mid-run, but did not narrow.

Recorded honestly: seasons 3 and 5 promoted ZERO. The near-duplicate gate
(normalised metric distance < 0.20 over air, largest share, walkable,
feature scale, clearance) is doing its job, but it also means the corpus
saturates at this scale. Five seasons of 24 demonstrates the MECHANISM, not
§3.3's "season 5 blends 200 discovered ones" -- that needs the overnight
budget, not a test.

Safety: a promoted record is RE-MEASURED on load, never trusted. Verified by
corrupting a stored metric -- the loader discarded it and re-derived the
geometry. A stale or tampered record therefore cannot introduce an
unescapable strate into a future season, which is the one failure that would
matter. Provenance (project/default/promoted) is tracked and logged.

Codex's recommendation, and I agree: keep a small explicit OUTLIER QUOTA
among candidates that pass every hard gate. This run showed no collapse, but
survivor-only promotion keeps the long-term risk, and a quota costs nothing.

PART A: the fine ROI now centres on LargestComponentPoint instead of (0,0).
Blank fine renders 6/42 -> 3/42. The label now reads "largest open space",
not "strate centre" -- the image moved, so the caption had to.

Build clean, 27 succeeded / 0 failed, verified by me. WorldRadiusVoxels=0.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VJiTcTSDNkKBtnNdiBtdaU

Source/VoxelForge/VoxelForge.Build.cs

@@ -79,6 +79,7 @@ public class VoxelForge : ModuleRules
 		// Private dependencies - only used in our .cpp files, not exposed in headers
 		PrivateDependencyModuleNames.AddRange(new string[]
 		{
+			"Json",           // Diffable Tier 5 promoted-record and season-manifest stores
 			"ImageWrapper",  // PNG encode for the biome-map preview bake (BakeBiomePreview)
 			"RHI",           // Texture3D create + RHIUpdateTexture3D for the density volume (mini-sun shadows)
 			"RenderCore",    // ENQUEUE_RENDER_COMMAND for the volume upload