Untangling the copilot dependency in @ag-ui/mastra

[alecf]

I'm trying to use the @ag-ui/mastra package in a project that isn't using copilotkit, but this package has a dependency, for a single function, on copilotkit - as I understand it, this is just a bit of legacy from when this was a deeper part of copilotkit. But I've had to fork the repo just so I can use the package.

I tried to start an issue here: #309 and even offered up a strawman PR here: #312 but I'm not getting any traction

Anyone have any opinions on the best place to move this function?

[NathanTarbert]

Hey @alecf, apologies for the delay. @maxkorp, do you have any insights here?