[Feature] Add support for OpenAI compatible providers

[ItachiSan]

🎯 The Goal / Use Case

I would like to have custom OpenAI compatible providers.
This would allow to add self-hosted routers e.g. 9Router.

💡 Proposed Solution

Add a custom provider, named "OpenAI Compatible".

🛠 Potential Implementation (Optional)

The provider can be a copy of OpenAI.
I'm currently using OpenAI with my 9router endpoint and key and works fine.

🚦 Impact & Roadmap Alignment

• This is a Core Feature
• This is a Nice-to-Have / Enhancement
• This aligns with the current Roadmap

🔄 Alternatives Considered

For now, just the workaround mentioned in the implementation section.

💬 Additional Context

Can provide if any!

[github-actions]

This issue has had no activity for 7 days and has been marked as stale. If it is still relevant, please reply or update; otherwise it will be closed automatically in 7 days.

[ItachiSan]

The issue is still valid, although no one replied to it.