[ENHANCEMENT] Add IBM watsonx AI provider in the list of providers to connect to IBM hosted LLMs

[PrasangAPrajapati]

Problem (one or two sentences)

I want to connect to IBM-hosted LLMs using Roo Code.

Context (who is affected and when)

I want to use the IBM-hosted LLMs using Roo Code.

Desired behavior (conceptual, not technical)

Users will now have the choice to connect to IBM-hosted LLMs using IBM watsonx AI provider

Constraints / preferences (optional)

No response

Request checklist

• I've searched existing Issues and Discussions for duplicates
• This describes a specific problem with clear context and impact

Roo Code Task Links (optional)

No response

Acceptance criteria (optional)

No response

Proposed approach (optional)

No response

Trade-offs / risks (optional)

No response

I'm exploring a potential fix for adding IBM watsonx AI provider support and will open a PR to share progress.

Hi @prasangap! I've opened PR #8091 with my attempt at addressing this issue. The implementation adds comprehensive support for IBM watsonx AI provider, including:

• Support for IBM Granite models (various sizes from 2B to 34B)
• Granite Code models for code generation
• Third-party models available on watsonx (Llama 3, Mixtral, Mistral)
• Proper integration with the existing provider architecture
• Region-based endpoint configuration

The PR is ready for review. Feedback welcome!