docs(assets): PR #211 review fixes — ratified glazing tokens, D-257, manifest skip contract

Review round (Hoshe + Tyre, both REQUEST_CHANGES) fully addressed:
palette.md's glass carve-out re-keyed from retired never-shipped tokens
(precision_glass/smart_facade) to the ratified glass_curtain_wall (wall)
+ industrial_glazing (facade); the toon/PBR treatment promoted from a
docs-only ruling to D-257 (architecture, cross-refs D-235/D-244/D-043/
D-044/D-033) with palette.md §2 now citing it as authority; D-149 +
D-257 added to decision_refs; manifest.json _comment gains the explicit
underscore-prefix loader skip contract; master pipeline table Visual row
Stub -> Active; conventions.md mask pointer Section 3 -> 5; pre-existing
broken D-066 links in the mood-board transcript repaired (leave-cleaner).

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

docs/assets/visual/conventions.md

@@ -45,7 +45,7 @@ T-1050).
 ## 2. Mask sidecars
 
 Convention: `<model>_mask.png`, single-channel (R-only greyscale), sitting
-next to the GLB — per the character-asset convention (Section 3,
+next to the GLB — per the character-asset convention (Section 5,
 `docs/architecture/character-asset-organization.md`). White = tintable
 region, black = preserve original texture (`hint_default_black`: no mask
 loaded = no tinting; assets without a mask render with their original