The assign_remainder (%=) case in Boxed_Number::go was missing the
check_divide_by_zero guard, causing a hardware SIGFPE on integer
modulo by zero. Also moved a misplaced check_divide_by_zero from
assign_bitwise_and (&=) where it was erroneous. Additionally, the
catch block in Equation_AST_Node::eval_internal was masking the
arithmetic_error exception as a generic "unsupported operation" error;
arithmetic_error is now re-thrown to provide the correct error message.
Co-authored-by: leftibot <leftibot@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
