Mixed arithmetic defect

The printed v7 real-interval multiplication method attempted to convert every right operand to a real interval. Expressions such as

therefore attempted to convert a complex rectangle to a rational scalar, before reflected multiplication could run. Reversing operands at individual call sites can avoid the immediate exception, but does not repair the type interface globally.

The v8 real class returns for complex operands, allowing the complex reflected method to handle mixed arithmetic. This follows Python's documented numeric dispatch convention PythonNumeric. Complex-valued calculations also use explicit complex promotion. Startup self-tests cover both multiplication orders.

This is a static repair. The exact patched v7 source used for the reported result remains unidentified.