- relay: SSE stream error exposure improvements (Claude/Gemini/OpenAI)
- test: add mock capture server for E2E relay capture testing

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

- Gemini stream: 捕获 promptFeedback.blockReason 后停止流并返回 OpenAPI 错误
- OpenAI stream: 检测 SSE 帧中的 error 响应，在首帧写入前转换为 API 错误
- Responses stream: 处理 response.error / response.failed / error 类型帧
- 新增 ClearEventStreamHeadersIfNotWritten 工具方法，错误转换时清除流式头
- 新增 streamOpenAIErrorFromData，从 SSE data 帧提取 OpenAPI 错误结构
- 上游错误体会截断后存入 UpstreamBody 供排障

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

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

删除用户渠道倍率（UserChannelRatio）功能，清理全链路相关代码：
后端删除 model/controller/router 层实现，前端删除 UI 组件和计费展示逻辑。
同时恢复 Token 分组选择和价格侧边栏分组过滤器的注释代码。

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

Add unit tests for group ratio, cross-group retry, and price calculation:
- Group ratio CRUD and special ratio override (12 tests)
- HandleGroupRatio with auto-group and special ratios (5 tests)
- ModelPriceHelper with group ratio in price/ratio modes (3 tests)
- Channel selection priority, groups, weighted LB (6 tests)
- RetryParam and AutoGroup service logic (7 tests)

Also restore the group pricing card in model detail SideSheet.

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>

为每个用户添加独立于全局定价的倍率乘数，支持按 (userId, model, channel) 三维
精确控制用户级别定价。倍率以乘法叠加在现有 modelRatio × groupRatio 之上。

- 新增 user_channel_ratios 表，写入内存缓存（写穿透模式）
- 新增 /api/user_channel_ratio/ CRUD API（AdminAuth）
- 计费路径集成：compatible_handler、PostClaudeConsumeQuota、
  PostWssConsumeQuota、PostAudioConsumeQuota、calculateAudioQuota
- 前端：EditUserModal 内嵌 UserRatioSection 组件
- 修复 Update() 缓存 key 零值 bug（先加载再更新）
- 修复 PreWssConsumeQuota 缺少 UserChannelRatio 导致归零
- 修复 ModelPriceHelperPerCall 缺少默认值 1.0

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

- logger: 增加 ctx nil 检查，避免系统级日志 panic
- relay: 将 DebugEnabled 下的 println 替换为 SysLog
- price: 修复渠道定价在 ChannelMeta 未初始化时的获取失败问题

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

- 后端 pricing API 从 channel_pricings 表获取实际定价，选取最便宜渠道
- 提取 applyGlobalDefault 辅助函数消除全局回退逻辑重复
- price.go 重构扩展比率为局部变量，简化回退逻辑
- 定价卡片新增缓存读取/创建价格，改为两行布局防止溢出
- ChannelPricingCard 缓存列显示实际价格而非倍率
- 修复移动端 hero 区域 padding 过大
- 默认标签页标题改为 Loading...
- 新增缓存读取/创建 i18n 翻译（7 语言）

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

- 提取 PriceData.ApplyChannelPricingRatios 消除 ModelPriceHelper 和
  UpdatePriceDataForChannelPricing 中重复的 ~30 行比率回退逻辑
- 提取 ChannelPricing.ApplyFields 消除 controller 中 4 处相同的字段赋值
- 提取 setCache/removeCache 辅助函数统一写穿透缓存操作
- 将 claudeCacheCreation1hMultiplier 常量移至 types 包避免循环依赖
- 修复 BatchUpsertChannelPricing 成功后未刷新内存缓存的 bug

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

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

实现 Master-Slave 架构的跨区域用户和配额同步功能，支持国内主节点与
海外从节点之间的用户创建推送、余额同步、预扣费批量回传。

主要变更：
- 新增 region_sync 服务层（SyncManager/SyncClient/推送逻辑）
- User 模型扩展 Source/RemoteUserId/SyncedQuota/LastSyncAt 字段
- BillingSession 支持 SyncedUserFunding 资金来源
- 新增 SyncAuth 中间件（X-Sync-API-Key + 常量时间比较）
- 新增 PendingSyncRecord/QuotaSyncLog 数据模型
- 前端新增区域同步配置面板
- 支持 SESSION_NAME 环境变量避免多节点 cookie 冲突

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

当模型配置了渠道定价但全局定价未设置时，不再提前报错。
将全局定价检查延迟到渠道选择后执行。

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

This PR fixes three issues:
1. Token bound_channel_id not updating: Add bound field to Update() method
2. Channel pricing quota_type detection: Use QuotaTypeByCall constant instead of magic number 1
3. Log display for ratio-based pricing: Set ModelPrice=-1 for ratio-based pricing

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

Integrate channel-specific pricing into the billing logic.
- First tries to get channel pricing using model.GetEffectivePricing
- If found, uses channel pricing (modelRatio, completionRatio, modelPrice, usePrice)
- If not found, falls back to global pricing from ratio_setting

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