Feature request: Add CometAPI as an LLM provider

[tensornull]

Is your feature request related to a problem? Please describe.
Chatbot UI users need provider redundancy and cost flexibility. Relying on limited providers causes downtime during rate limits or outages. CometAPI (OpenAI-compatible) would improve reliability without changing existing workflows.

Describe the solution you'd like

• Add CometAPI as a first-class LLM provider or support custom baseURL in OpenAI integration
• Support chat features: text generation, model selection, API key management, streaming
• Environment variables like existing providers (e.g., COMETAPI_API_KEY)
• Filter non-chat models from CometAPI's model list

Describe alternatives you've considered

• Using OpenAI integration with custom baseURL—works but not obvious
• Third-party proxies—adds dependencies
• Current providers only—limits resilience

Additional context
CometAPI Resources:

• Website: https://www.cometapi.com/
• API Documentation: https://api.cometapi.com/doc
• Base URL: https://api.cometapi.com/v1/
• Model List: https://api.cometapi.com/v1/models
• Get API Key: https://api.cometapi.com/console/token
• Pricing: https://api.cometapi.com/pricing

Compatibility:

• OpenAI-compatible endpoints, enabling seamless integration
• Supports streaming responses for real-time chat
• Filter needed for non-chat models (image/audio/video generation)

Implementation Offer
If you are willing, we can implement this and submit a PR containing documentation, examples, and test API keys for verification.