pr-fixup

# PR Fixup Use this workflow directly in the user-started primary conversation. Do not launch a verifier, implementer, or other remediation subagent. A read-only `pr-poller` is the sole exception: launch it only when the user explicitly asks to wait for or monitor PR updates. For a cost-controlled workflow, the user may switch the same conversation to the lower-cost implementation/test model before starting CI remediation. Use `gh` by default; when it is unavailable after access is approved, use an available GitHub integration. `scripts/pr-state`, `scripts/pr-resolve`, and `scripts/run-quiet` are at the worktree root. ## Pipeline Create a visible checklist: 1. Gather PR state 2. Fix failing CI checks 3. Triage review comments 4. Address valid comments 5. Commit, rerun affected checks, and push 6. Re-check the new head 7. Report ## 1. Gather PR State Before the first GitHub helper call, request any runtime network approval that the environment requires. If access is denied, cancelled, or interrupted, stop the workflow permanently; retry only transient fetch failures after access is approved. Run `scripts/pr-state --summary <PR>` once. Record `checks_head_sha`, `checks_snapshot_complete`, `failed_checks`, `pending_checks`, `unresolved_review_thread_count`, `hidden_unresolved_threads`, and `actionable_issue_comment_count`. Inspect mergeability separately through `references/merge-conflicts.md`; it is not a `pr-state --summary` field. If a named reviewer is the semantic e...