Carbons

Carbon 1.21.1.9-B (0.9-B)

• Preserve Iris first-person hand shaders during item instancing, correcting material and lighting differences on held items and glass.
• Bind only valid user vertex attributes in derived shader programs; exclude built-in inputs such as gl_VertexID.
• Retain the 0.9-A Chloride compatibility fixes, physical dropped items and cache update budget.