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) |

No files, tests, or entry points are named. Start by inspecting the desktop app's settings UI and the existing agent and provider/model configuration; done means users can add and edit agents and can view available models grouped by provider.

索引モデルが issue の本文から書いたものです。