model-verify-flagos

验证服务栈，使用用户指定的目标模型。运行两次：首先在禁用FlagGems/FlagCX的情况下运行（隔离特定于模型的错误），然后启用完整的多芯片堆栈再运行一次。比较这两次运行的结果，以确定是哪一层导致了任何失败。

Verify the serving stack with a user-specified target model. Runs twice: first with FlagGems/FlagCX disabled (isolate model-specific errors), then with full multi-chip stack enabled. Diffs the two runs to pinpoint which layer caused any failure.