NocoBase v2.0.0-alpha.15: Add new LLM providers

🚀 Improvements

• [client] support association fields in JS field model (#7618) by @gchust

• [AI employees]

  • Refactored the OpenAI LLM Provider into two separate providers to support OpenAI’s Completions and Responses APIs. (#7615) by @cgyrock

  • Add new LLM provider Ollama (#7612) by @ReLaMi96

🐛 Bug Fixes

• [Workflow: Approval]

  • Fix the issue where task count not updated after added assignee by @mytharcher

  • Fix the transaction timeout issue caused by transactions not rolling back properly when database errors occur after approval submission by @mytharcher