Raise character limits and document optional Blender MCP

.agents/skills/gig-line-blender-asset-contract/references/asset-contract.md

@@ -17,7 +17,7 @@ This is a working summary. The authoritative sources remain
 
 ## Skeleton and geometry
 
-The contract skeleton has 13 bones:
+The required contract skeleton has 13 core bones:
 
 ```text
 Head, Spine, Neck,
@@ -28,6 +28,9 @@ ElbowL, ElbowR,
 HandL, HandR
 ```
 
+Optional extra bones (fingers, face controls, toes) are allowed if they do not
+move these core rest positions and do not break `NpcAvatar`'s animation proxies.
+
 Requirements:
 
 - `npc_base` mesh node exists and is skinned under `Rig`.
@@ -56,8 +59,7 @@ skin, cloth, pants, accessory, hair
 
 | Asset | Limit |
 | --- | --- |
-| Library character | 8,000 triangles / 8,000 glTF vertices |
-| `npc_base` fallback | 6,000 triangles / 4,000 vertices |
+| Character (library and base fallback) | 16,000 triangles / 16,000 glTF vertices |
 | Gear piece | 1,500 triangles |
 | Prop | 4,000 triangles |
 | Library prop/venue total | must stay inside the venue tests and library budget |