Add translucent block rendering (glass, water, ice)

[Purdze]

Summary

• Parse 26.1.1 texture format and classify translucent blocks (glass, stained glass, water, ice)
• Add separate translucent rendering pass with its own pipeline and fragment shader
• Extend chunk buffer/mesher to handle translucent geometry alongside opaque

Test plan

• Glass and stained glass render with transparency
• Water and ice render correctly
• Opaque blocks unaffected
• No perf regression on chunk meshing