ClosedBit error docs

CB_ERR_GPU_UNAVAILABLE

GPU unavailable. The selected GPU backend could not be created.

Why it happens

The selected GPU backend could not be created.

How to fix it

Update drivers, use a supported GPU, or rebuild without the GPU path.

Copy-paste fix pattern
compile cba app.cbp app.cba small compute
Runtime and Studio now show this kind of page from the error dialog: plain message first, stable code second, original details third.