Add automatic numeric-to-Complex promotion and simplify mitternacht test and fix test pipeline

[TriedAngle]

Motivation

• Allow mixed numeric/complex arithmetic to work without explicit Complex construction so tests and user code rely on implicit promotion instead of calling Complex directly.
• Fix the failing mitternacht test by avoiding module name collision and depending on automatic numeric promotion for negative-discriminant quadratic roots.

Description

• Added asComplex methods to Fixnum, Bignum, Ratio, and Float in core/math.ktt to return Complex clone setRe: self Im: 0 so numeric values can be promoted to Complex automatically.
• Ensured Complex provides asComplex = { self } so mixed operations call a consistent conversion method.
• Updated tests/mitternacht.ktt to rename the helper to Quadratic, remove explicit Complex constructions, compute denom and negB as plain numeric expressions, and print both roots for in-file validation.

Testing

• Ran python run_tests.py, which built the VM and executed the test suite successfully with 17 passed / 0 failed / 0 skipped.
• The project compiled in release mode and the updated test tests/mitternacht.ktt passed under the new implicit promotion behavior.

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Codex Task