feat: add explicit inputs/outputs protocol

[teelaitila]

Note: This is my take on solving this. Totally happy to adjust direction or make changes if you think there’s a better way.

Introduces an explicit multi-output test-case protocol:

test_generator now returns:

(inputs, outputs, expected)

What changed

• C++ benchmark flow now keeps inputs, outputs, and expected separate.
• Kernel launch is now kernel(*outputs, *inputs).
• Result checking now validates each output tensor (not just the first output).
• Updated Python types/docs to match the new format.
• Updated exploit fixtures to the new multi-output kernel signature.

Note

This is a breaking change for test_generator return format.

Old:

return (out, x), (expected, rtol, atol)

New:

return (x,), (out,), ((expected, rtol, atol),)

Tested on Modal with both single-output and multi-output grayscale cases.

[ngc92]

there are also in/out args, such as C += AB in a gemm. Would be nice if we could support this, too, and I'm not sure if this approach generalizes well. Otherwise, I like it.