希望在用量和计费里加入token用量信息

### 使用场景 / Use case

现阶段使用时会有切换模型使用的情况，但是目前并没有一个能够统计每种模型的使用量以及总使用量的显示窗口，建议将此功能放置于某一合适位置

### 当前问题 / Current limitation

token用量统计功能略模糊

### 期望方案 / Proposed solution

_No response_

### 已考虑的替代方案 / Alternatives considered

_No response_

The issue requests a usage and billing view showing token counts for each model and an overall total, but names no files, tests, or entry points. First locate the existing usage or billing interface and determine where model usage data is recorded. Done means users can view per-model token usage and the aggregate total.

Written by the indexing model from the issue text.