GitLab

Backend: Fix three race conditions in SetSnapshot that caused account
scheduling anomalies and broken sticky sessions:
- Use Lua CAS script for atomic version activation, preventing version
  rollback when concurrent goroutines write snapshots simultaneously
- Add UnlockBucket to release rebuild lock immediately after completion
  instead of waiting 30s TTL expiry
- Replace immediate DEL of old snapshots with 60s EXPIRE grace period,
  preventing readers from hitting empty ZRANGE during version switches

Frontend: Remove serial queue throttle (1-2s delay per request) from
usage loading since backend now uses passive sampling. All usage
requests execute immediately in parallel.

LoadFactor 字段在构建调度快照缓存时缺失，导致调度算法
EffectiveLoadFactor() 无法使用配置的负载因子，回退到 Concurrency。
这会影响账号的负载率计算，进而影响调度优先级。

修复：在 buildSchedulerMetadataAccount 中添加 LoadFactor 字段。

当新分组创建后立即绑定账号时，调度器会错误地将空快照视为有效缓存命中，
导致返回没有可调度的账号。现在空快照会触发数据库回退查询。

- 调度热路径优先读 Redis 快照，保留分组排序语义
- outbox 回放 + 全量重建纠偏，失败重试不推进水位
- 自动 Atlas 基线对齐并同步调度配置示例