The settings lack a section: adding agents, editing agents.

The settings lack a section: adding agents, editing agents. Now the work of agents is not clear. It is also necessary to add the separation of available models by providers. Now it is not clear if a person uses 2 or more providers for 1 and the same model and to separate by names is not very good. It would be great to get a block of each provider with available models

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| Field | Value |
| --- | --- |
| App version | 1.1.2 |
| OS | Windows 10.0.26200 |
| Theme | GitHub |
| Path | / |
| Tenure | Day 3 (Week 1) |

未指定任何文件、测试或入口点。首先检查桌面应用的设置 UI，以及现有的 agent 和 provider/model 配置；当用户可以添加和编辑 agent，并按 provider 分组查看可用模型时，即视为完成。

由索引模型根据 Issue 内容生成。