Document builtin overloads that jet spaces add at runtime, such as wp.value() on scalar jets #2311

Documentation gap

Forward-mode jets (GH-1813) attach overloads to existing builtins when a wp.JetSpace or wp.JetSpace2 is created: wp.value(), and jet versions of wp.sin(), wp.length(), wp.svd3() and so on. The generated API reference lists only the overloads registered at import time, so for example the wp.value() page shows only float16/float32/float64 signatures and looks like an identity function, even though its main use is extracting the value of a scalar jet.

The docstrings now describe the jet arguments in prose (for wp.value(): an instance of J.scalar for a space J, with a doctest). What remains is to make such runtime overloads visible in the generated reference, for example by:

• listing, on each builtin's page, that jet spaces add overloads for it, with a link to the jets guide; or
• documenting the jet overloads once, as a table in the jets guide or API reference, rather than per builtin.

This was split out of the jets review to avoid extending the Sphinx builtin-reference machinery in that MR.

This issue was written by Claude Code on behalf of @alecjacobson.