Add support for projects

[jonathanKingston]

Consider support for linking a thread to a projectId. This would allow agents to clearly group together work even though their cwd might be completely different.

In the Codex client their API supports project creation and naming, they also support the projectId being passed.

This would address the Codex client having many single threads each for different working trees making it hard to see project work. For example:

This is caused by my agent giving codex a unique working directory, naming them all the same won't work either.