后端执行：执行架构
一个策略执行点将租户范围的行过滤器应用于查询、搜索、导出、作业和聚合，在缺少上下文时关闭失败，并且绝不将客户端提供的租户 ID 视为权威。
Effective permissions are computed deterministically from role, group, and resource inheritance with deny-wins rules, materialized views for audit, and explicit handling of grant overlays.