participatesInDebugViews property

Whether this material's fragment shader declares the DebugViewInfo block and switches on it (see material_debug.glsl), so the scene's surface debug views can show its resolved surface.

Every engine material and every .fmat participates. A raw ShaderMaterial opts in through its constructor after including the hook; one that does not is drawn through the engine's fallback debug shader while a view is active, which serves the geometry and identity channels and stripes everything else.