Add affine virtual booleanity MLEs

[latifkasuli]

Next atomic follow-up after #221 for #185, which blocks #91.

What changed

• Adds UairSignature::num_booleanity_bin_cols() as the signature-derived count for committed witness binary columns plus affine virtual booleanity targets, without changing committed/PCS column counts.
• Adds build_affine_virtual_bit_slice_mles for materializing affine virtual residual bit-slice MLEs from binary source columns, including shifted terms and 1_D offsets.
• Adds prepare_affine_virtual_sumcheck_group, which routes affine virtual targets through a separate generic degree-3 booleanity group instead of the BinaryPoly round-1 fast path.
• Adds focused UAIR and PIOP tests for accounting, residual materialization, shifted/ones offsets, and an accept/reject affine virtual booleanity roundtrip.

Intentionally deferred

• Protocol consumption of num_booleanity_bin_cols() is deferred to the next atomic PR.
• The alpha-prime bridge that binds affine virtual bit-slice claims back to committed source openings is deferred to the soundness-closing follow-up.
• SHA-256 Ch/Maj adoption remains a later PR after the protocol wiring is merged.

Validation

• ./.githooks/pre-push