Cover zero operands, power-of-2 fast path, negative operands,
balanced multi-limb pairs with a shared Fibonacci factor, highly
unbalanced pairs (to exercise the Euclidean fallback), and
Fibonacci neighbors (always coprime). Declare a test dependency
on mruby-numeric-ext since Integer#gcd is defined there.
Co-authored-by: Claude <noreply@anthropic.com>
Fixed non-commutative multiplication bug where operands with different
limb counts would produce different results based on order (a*b \!= b*a).
Root cause was asymmetric carry propagation in the multiplication algorithm.
The fix ensures consistent operand ordering by always processing the smaller
operand first in the nested loops, making multiplication truly commutative.
Also fixed division algorithm quotient allocation and qhat refinement.
Co-authored-by: Claude <noreply@anthropic.com>
Yukihiro "Matz" Matsumoto