- 新增 API 端点获取模型在各渠道的定价信息，支持全局价格回退
- 在模型详情侧边栏添加渠道价格卡片，显示所有支持该模型的渠道
- 优化 HorizontalFilterRow 组件，改用 flex-wrap 自动换行布局
- 隐藏数量为 0 的模型类型筛选项

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

- GetAllChannelPricing: get all channel pricings with pagination
- GetChannelPricingByModel: get pricings for a specific model
- CreateChannelPricing: create or update channel pricing
- BatchCreateChannelPricing: batch create/update pricings
- DeleteChannelPricing: delete channel pricing
- CopyGlobalPricing: copy global pricing from ratio_setting to channel
- GetChannelPricingWithTags: get pricings with tag details

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>