[Feature]: Add support for Zed as a provider

[stefanbinoj]

Why

Since Zed has given out $10 free inference for all students across world, It would be really nice if i could use that inference in the same app without swithcing.

Ready to file a PR if this gets a scope! k

Reference PR's:

#2185
#1758

[juliusmarminge]

Zed inference is not exposed through a stable supported agent protocol here, and the earlier experimental pull requests did not establish a maintainable adapter. With no additional demand, this provider is out of scope.

This was closed as part of a large repo-wide maintenance sweep. If you think it's still relevant, please reopen.