Variable dropUnusedTextureConst

dropUnusedTexture: Fix = ...

Auto-fix for TEXTURE_UNUSED — destroys a SceneTexture that no SceneMaterial binds. SceneTexture.destroy guards against destruction while numMaterials > 0, so a stale issue (raced with concurrent material reattachment) surfaces as the underlying SDK error rather than a corruption.

Idempotent: returns {fixed: false} when the texture is already destroyed or absent.