nerdamer.div

This is the parser-facing compatibility behavior historically exposed as div(a,b). It delegates to the existing polynomial division implementation. When more than one variable is present, Nerdamer treats the input as a multivariable polynomial rather than silently choosing one variable and treating the others as coefficients. If either input is not polynomial-like, the legacy fallback is preserved as [0, dividend]. Once both inputs are polynomial, failures from the division engine are allowed to propagate.