There should be a filter for those who have a LOT of session repos

When a user has a large number of session repositories loaded within github app, it can be difficult to manage.

Request: There ought to be a very simple UI based sorting and filtering set of controls, that includes a filter by name (via substring)

Example of the issue:

---
| Field | Value |
| --- | --- |
| App version | 1.0.26 |
| OS | macOS 26.5.1 |
| Theme | GitHub |
| Path | /chat |
| Tenure | Week 6 |

从加载会话存储库的 /chat 视图开始，检查现有的存储库列表 UI。添加简单的排序和筛选控件，包括按名称进行子字符串匹配，然后验证用户可以缩小范围并管理大型存储库列表。

由索引模型根据 Issue 内容生成。