[FEATURE]: Assign issues to the contributor by using the slash command in discord.

### Feature and its Use Cases

We have to add a feature that allows maintainers to assign issues to contributors using a Discord slash command:

`/assign-issue`

**Please do not message here asking to assign this work to yourself.** Instead, submit a proposal explaining how you would implement this feature with minimal code while maintaining good code quality and following the project's existing architecture.

If your proposal is feasible and aligns with our requirements, I will assign the issue to you so you can implement it.

### Additional Context

_No response_

### Code of Conduct

- [x] I have joined the [Discord server](https://discord.gg/hjUhu33uAn) and will post updates there
- [x] I have searched existing issues to avoid duplicates