Changes
PR #1852 by ksylvan: Add Abacus vendor for ChatLLM models with static model list
- Add static model support and register Abacus provider
- Detect modelsURL starting with 'static:' and route appropriately
- Implement getStaticModels returning curated Abacus model list
- Register Abacus provider with ModelsURL 'static:abacus'
- Extend provider tests to include Abacus existence