PR Issue 自动 Fix

The operator can turn a PR issue into a controlled fix loop without manually rewriting the review comment as an agent plan.

• 1
  public metadata 可以进入 packet；raw issue body、comment body、timeline、provider payload 都是 gated source。
• 2
  accepted candidates 写成有序 LoopX todos：repro smoke、code-context route、branch-local patch、validation、review-packet readiness。
• 3
  caller-approved repo 模式只在 `--execute` 时检查本地 repo，并且输出 repo-relative changed files、validation pass/fail 和 PR-readiness。
• 4
  外部 comment、PR creation、merge、publish、destructive git 和 production action 都保留为显式 gate。