Remove `@octokit-next/core` package from dependencies

[babblebey]

The @octokit-next/core package, which was added to project dependencies in #32, It was used as a lightweight alternative to integrating Octokit in the handleSubmitWord handler which was introduced by the same PR (#32); This was done because we needed to bring instantiation of octokit for current user and jargons.dev app to the client-side for consumption (this don't matter now - don't let this confuse you haha 😆)

Following #53, we have moved on and removed the handleSubmitWord handler and moved all the its operation to an API route which means we no longer require instantiating any octokit on the client hence sticking to the singleton instance available of the jargons.dev app on the server and instantiating one for the user with their accessToken that gets sent to the server through cookies present in their request to the API route;

So, We no longer have any need for the @octokit-next/core package. Hence we should remove the @octokit-next/core package from the project.

Fun Fact:

This package was infact wrong and shouldn't have been installed in the first place by "Ola" (I wonder who that was 🤔😉), the package is an experimental SDK and stated in its doc is a "DO NOT USE" notice. See https://github.com/octokit/octokit-next.js?tab=readme-ov-file#octokit-nextjs

Steps:

1. Remove the @octokit-next/core package from the dependencies in the package.json file.
2. Run the npm install command to update the package-lock.json file and remove the @octokit-next/core package.

Expected Behavior:

• The @octokit-next/core package should be removed from the project dependencies.
• The project should still build and run correctly after removing the @octokit-next/core package.

Additional Information:

• This change is necessary to clean up the project dependencies and ensure that only the required packages are included in the project.

[amiabl-programr]

Can I be assigned to this issue?