This reverts commit d61b04a.

…odels

- Add safety checks in /provider endpoints before accessing sortedModels[0].id
- Prevent 'undefined is not an object' error when providers have empty models
- Return undefined instead of crashing for providers with no available models
- Fixes both /provider and /provider endpoints with filtering

Fixes error: Provider.sort(Object.values(item.models))[0].id

Updated ToolPart import to use v2 SDK to match sync store types.
Resolves TypeScript error introduced by merging dev branch.