numberize - rewrite only positive leaves, add map value numberization

[lukaszsamson]

Addresses 1 and 2 from #15799
Extracted from #15800

AssistedBy: Claude Fable 5, GPT 5.6 Sol

[josevalim]

Now I am thinking... isn't our bdd_map inherently wrong because it may rewrite the leafs which means they have a different ordering? I am thinking everything needs to be written as in this formula... which would also make numberize too expensive...

[lukaszsamson]

I recall one of AI reviews flagged the order not being preserved as an issue. I wasn’t able to produce code where it would surface as an evident bug. I dismissed the proposed fix with BDD rebuilds everywhere as a bad tradeoff

[josevalim]

@lukaszsamson I am thinking a better solution here would be have a field in the context called numberize. So when we assemble the type here:

  defp custom_compare(name, arg, literal, expected, expr, stack, context, of_fun) do
    case booleaness(expected) do
      booleaness when booleaness in [:maybe_both, :none] ->
        compare(name, arg, literal, false, expr, stack, context, of_fun)

      {boolean, _maybe_or_always} ->
        {type, context} = of_fun.(literal, term(), expr, stack, context) # <=======

We set this value in the stack and we interpret all integers/floats in the literal as numbers. This makes it correct by construction and we can remove numberize.

We still have to address 3 from 15799 though... perhaps we have a version of disjoint that ignores numbers... but that may be complicated.