feat: add ZenMux inference provider

[mingcheng]

• add ZenMux to list of supported providers in README
• implement ZenmuxConversationalTask for conversational AI
• update provider mappings and imports in getProviderHelper
• add zenmux to hardcoded model inference mapping
• include ZenMux in provider types and hub organizations

[mingcheng]

Hi, We are the ZenMux AI Team. We are AI FORCE SINGAPORE PTE. LTD, a team driven by technological innovation. Our vision is to fundamentally revolutionize the way AI applications are developed by eliminating infrastructure complexity and guaranteeing reliability.

ZenMux is our core platform, it is positioned as the world's first Enterprise-Grade Model Aggregation and Quality Assurance Solution that will deeply integrate AI Model Insurance Services. Our goal is to provide developers with a unified, stable environment that delivers the highest level of assurance for calling large models.

[mingcheng]

Hello, @julien-c.

Given that a week has passed, please let me know when this PR can be merged.

So many thanks