FEAT: Update ai packages

[7alip]

Is your feature request related to a problem? Please describe.

There are some deprecations in the last ai and openai packages. When you update these packages, the functionality doesn't work.

Describe the solution you'd like

Adjust current gen-archive-content-posts and route-tweet-gen api routes. Here an example: https://github.com/vercel/ai/blob/main/examples/next-openai/app/api/completion/route.ts

Additional context

To save money, in development mode, we use the generateMockTweets function rather than making an actual request to openai. This function may need to be adjusted as well.