chore(skills): unify PR monitor loop stop condition to 3 consecutive clean passes (#3285)

Author: PierreBrisorgueil

.claude/skills/pull-request/SKILL.md

@@ -135,7 +135,7 @@ REPEAT:
   6. If actionable comments             → fix all, /verify, commit, push, reply, resolve, consecutive_zero=0, GOTO 1
   7. If non-actionable unresolved       → reply all explaining why, resolve all, consecutive_zero=0, GOTO 5
   8. If zero unresolved threads         → consecutive_zero++
-                                           if consecutive_zero >= 2 → check branch protection (see 6f), then STOP ✓
+                                           if consecutive_zero >= 3 → check branch protection (see 6f), then STOP ✓
                                            else GOTO 3
 ```