feat(anyint): add AnyInt provider

[blandon-zhou]

Summary

• add AnyInt as an OpenAI-compatible provider at https://api.anyint.ai/openai/v1
• include current flagship models plus mainstream multimodal/image/video models exposed by AnyInt model discovery
• omit static provider pricing because AnyInt pricing is dynamic and should be referenced from the AnyInt website

Validation

• bun validate
• git diff --check