Actually usable transitive params

[jtoman]

The previous approach yielded correct schemas, but if you tried to use these templates within a tool body, pyright would throw a fit. It would conclude that when you wrote:

@tool_family(...)
class OtherType:
  ...

@tool_family(...)
class MyThing:
   my_field: OtherType = ...

that my_field was a _TemplatedTool, and thus only supported with_template calls; the natural use within the body of MyThing as an OtherType would cause pyright to complain. At runtime, this was all fine: after template instantion in MyThing, my_field would actually be an instance of (a subtype of) OtherType. Pyright had no way to know this, and I wasn't willing to gloss over it with the type: ignore comments that would be required everywhere.

The solution is a new type of annotation: family_param. This decorator will rewrite the annotated type T to be a new subclass of _TemplatedTool[T] and T itself. Thus, the result of the annotation can be used like any other BaseModel. The black magic runtime subclassing checks in the "top level" @tool_family all still "just work"; the result of the family_param annotation triggers the subclassing check against _TemplatedTool; the only difference is that it just unwraps back to "itself".

Verified against the motivating use case upstream in autoprover

[ericeil]

Looks as good as I'd expect this sort of thing to look. :)