Delete leftover channel pricing controllers and routes after removing channel pricing, and align relay price helpers with global pricing plus user channel ratio only.

Co-Authored-By: Codex <noreply@anthropic.com>

使用注释方式隐藏分组列和分组倍率标签，便于后续恢复：
1. 注释 UsageLogsColumnDefs.jsx 中的分组列定义
2. 注释 useUsageLogsData.jsx 中的 COLUMN_KEYS.GROUP 和默认可见性配置
3. 将计费详情中的"分组倍率"改为"倍率"

后端计费逻辑不变，仍正常应用分组倍率。

Co-Authored-By: Claude Sonnet 4 <noreply@anthropic.com>