refactor: 移除「职位」概念,仅保留「角色」管理权限

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
1 job for develop in 13 minutes and 23 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #131003
studio
ci-build

00:13:23