docs(vm1): closeout - AP-232 for the translucent detail blend weight; sampler test pins the production constant

Opus narrow re-review of ae651312: APPROVE. Closes its three residuals:
- AP-232 filed: retail's single-pass stage-1 OUTPUT alpha
  (MODULATE(TEXTURE, CURRENT) @0x0059c549) is the blend weight for a
  translucent subset; acdream's two-draw model is exact for opaque
  subsets (fog identity pinned) and a bounded weight difference on
  translucent ones. Distinct from AP-34 (queue order). Owed since
  05970306.
- TerrainAtlas.DetailSamplerDescription names the production sampler
  (WRAP/LINEAR x3 per ACRender::SetDetailSurfaceInternal @0x006b6280);
  the test now asserts that constant's properties instead of a
  test-local copy.
- Plan VM1 section: fragment now described as fogged; VM1 marked CLOSED
  with the Holtburg measurement (+2.17/+0.57/+0.16 vs predicted
  +2.2/+0.66/+0.16) and the detail-on cost (+0.3-0.5 ms CPU at Arwic).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/research/2026-08-21-retail-building-detail-texturing-pseudocode.md

@@ -193,7 +193,7 @@ draw weighted by `detail.a * diffuseAlpha` (the pipeline in
 opaque subsets this is identical (both reduce to the base's own alpha
 gating nothing else downstream); on translucent building/EnvCell subsets it
 is a bounded difference in how much the SUBSEQUENT alpha-queue compositing
-sees, already covered by the existing AP-34 shared-alpha-queue divergence
+sees, registered as its own row AP-232 (blend WEIGHT on translucent subsets), distinct from AP-34 (queue ORDER)
 row rather than a new one.
 
 ## Darkening, not brightening