Allow ConvexVector and ConvexStorage to be used from a remote Mastra server

[ianmacartney]

Sequencing, for anyone who wants to push it forward before I do:

1. Change the ConvexVector implementation to take in a ConvexHTTPClient and a location, like api.myMastra where functions will be exported, along with an apiKey secret you create.
2. Add a class with no imports to Mastra's vector / memory that has a method to export a public API for all the required functions for the remote ConvexVector to hit. e.g. to be used like export { searchMessages, ... } = mastra.vectorApi({ apiKey: process.env.MASTRA_API_KEY });
3. Add functions to that class, without importing from Mastra, so you can use it from Convex to fetch messages / search / etc. So it can be reactive, but not be exactly a subclass of MastraVector / etc.

[stelloprint]

I'm seeing community interest on the Mastra side as well. It looks like there is an open PR: mastra-ai/mastra#5883

[vishesh-baghel]

@stelloprint This looks like a great extension to the existing MastraVector class. I will try something and keep this thread posted.