Locks in Decision 2 (Opaque + ClipMap → opaque indirect; AlphaBlend +
Additive + InvAlpha → transparent indirect). Catches future refactors
that drift the partition — silent visual regression otherwise (groups
rendered in the wrong pass with the wrong blend state).
Adds public static IsOpaquePublic shim on WbDrawDispatcher; the
underlying IsOpaque stays private.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
