fix(goal): bind no-follow-up ACKs to lifecycle truth

[huangruiteng]

Summary

• Reject coverage-backed no-follow-up when the same writeback keeps the vision open or the path continuing.
• Keep Todo succession authoritative: a semantic ACK cannot retire a completed-without-successor gap; only a typed runnable successor or durable Todo no-follow-up settlement can resolve it.
• Point repair guidance to loopx todo complete --no-follow-up and explicitly reject synthetic user gates.
• Consolidate the typed Todo succession reason/filter so write and read paths consume the same current gap truth.

Why this is separate from #3261

#3261 makes Todo completion continuation explicit and provides the narrow same-Turn recovery seam. This PR closes the cross-contract gap where progress/vision ACK state could still claim terminality without that durable Todo settlement.

Validation

• 199 model-behavior and focused goal-frontier tests passed.
• 162 broader goal-frontier/quota tests passed (covered within the 199-test run plus a prior focused pass).
• 59 direct regression tests passed after final refinement.
• Ruff passed on changed Python and tests.
• Control-plane maintainability ratchet passed.
• loopx canary premerge --from-git-diff: 18/18 selected checks passed, no manual holds.
• Public/private boundary scan passed.

Closes #3264.

[huangruiteng]

Summary

• Reject coverage-backed no-follow-up when the same writeback keeps the vision open or the path continuing.
• Keep Todo succession authoritative: a semantic ACK cannot retire a completed-without-successor gap; only a typed runnable successor or durable Todo no-follow-up settlement can resolve it.
• Point repair guidance to loopx todo complete --no-follow-up and explicitly reject synthetic user gates.
• Consolidate the typed Todo succession reason/filter so write and read paths consume the same current gap truth.

Why this is separate from #3261

#3261 makes Todo completion continuation explicit and provides the narrow same-Turn recovery seam. This PR closes the cross-contract gap where progress/vision ACK state could still claim terminality without that durable Todo settlement.

Validation

• 199 model-behavior and focused goal-frontier tests passed.
• 162 broader goal-frontier/quota tests passed (covered within the 199-test run plus a prior focused pass).
• 59 direct regression tests passed after final refinement.
• Ruff passed on changed Python and tests.
• Control-plane maintainability ratchet passed.
• loopx canary premerge --from-git-diff: 18/18 selected checks passed, no manual holds.
• Public/private boundary scan passed.

Closes #3264.

[huangruiteng]

Approval conclusion (author-owned PR; GitHub blocks formal self-approval)

精确评审头（Exact Head）: 3270@152acda4ba4d7bcd49d10ce6de761b583bd34654
Base: main | 类型: no-follow-up ACK 绑定 Todo 生命周期真相（13 files, +~300）
作者: huangruiteng（owner）

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详细中文评审

动机

关闭 #3264：此前 refresh-state 可接受 coverage-backed result_class=no_followup，但同一 writeback 保留 open vision / continuing path，语义 ACK 能清掉 completed-without-successor 义务却没有结构化 Todo no_followup=true，导致投影裂缝与合成 user gate。本 PR 把“语义 ACK”与“Todo 生命周期结算”彻底分开。

改动思路

三处收口：(1) semantic_delta_from_writeback 只在 agent_vision.state=no_followup 且 path_delta.outcome=stop 时接受 coverage_backed_no_followup；(2) qualify_replan_writeback 在存在 Todo succession gap 时拒绝 coverage-backed no-followup，并给出 loopx todo complete --no-follow-up 修复指引；(3) ack_policy 在 succession gap 打开时只接受 new_runnable_successor outcome。写/读共用同一 typed todo_succession_gap_items（reason-code 归一）。

具体改动

• progress_observation.py：no-followup 一致性校验（reason_code no_followup_vision_path_inconsistent）。
• semantic_replan_writeback.py：Todo gap 打开时拒绝并给修复命令（reason_code todo_no_followup_settlement_required），enforce_open_replan_writeback 对带 reason_code 的拒绝直接抛带指引的 ValueError。
• ack_policy.py / goal_frontier/__init__.py：gap 打开时 outcome 集合收窄到 new_runnable_successor；提示文案明确 “do not invent a user gate”。
• succession_warning.py / todo_summary.py：consolidate todo_succession_gap_items 与 reason code，recommended_action 指向 todo complete --no-follow-up。
• 文档：project-agent-todo-contract 与 goal-vision-replan-contract 明确“coverage evidence ≠ lifecycle settlement”。
• 测试：vision/path 一致性参数化、语义 ACK 不能替代生命周期结算（含持久化 ACK 回归）、ack policy successor-only、structured terminal settlement 不再触发 stale Next Action repair。

关键内容讲解

1. 一致终态才接受：no_followup ACK 必须同时满足 vision state=no_followup 与 path outcome=stop，否则 outcome 被移除且 accepted=False。
2. Todo 优先：只要 completed-without-successor gap 仍打开，任何 coverage-backed no-followup 都不能 ACK replan 义务；必须先 todo complete --no-follow-up 或加真实 successor。
3. 禁止合成 gate：修复文案与 projection 都明确“不要为压制 succession warning 而伪造 user gate”——正是 #3264 的核心验收项。

对主干的风险

无阻断项。改动集中在 goal-frontier/replan writeback 判定面，行为收紧符合 #3264 验收；不改变 benchmark 评分/任务语义。CI：Sign-off、build ×2、dependency-review 均 SUCCESS，pytest IN_PROGRESS（无失败）。

验证矩阵（exact head 实测）

场景	结果
test_goal_terminal_no_followup / test_progress_observation / test_refresh_state_replan_gate / test_replan_novelty_policy	59 passed
test_goal_frontier_replan_rules / test_replan_semantic_action_behavior / test_replan_host_context_projection / test_visible_goal_terminal_settlement	52 passed
作者 canary premerge	18/18 selected checks，无 manual holds
ruff / maintainability ratchet（作者）	PASS
CI：Sign-off / build ×2 / dependency-review	SUCCESS
pytest（CI）	IN_PROGRESS（评审时刻）

我的整体评价

精准命中 #3264 的三个验收项（拒绝不一致 no-followup、语义 ACK 不能替代 Todo 结算、修复指引不造 user gate），读/写共用同一 typed gap 真相，111 个相关测试在 exact head 全绿。结论：APPROVE（author-owned PR，以 COMMENTED 记录批准结论；合并前确认 CI pytest 绿）。

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English Verdict

Verdict: APPROVE (author-owned PR; recorded as COMMENTED because GitHub blocks formal self-approval). This change closes #3264 exactly: coverage-backed no-follow-up is accepted only when vision closes (state=no_followup) and the path stops, a semantic ACK can no longer retire a completed-without-successor gap without durable todo complete --no-follow-up settlement, and repair guidance explicitly forbids inventing a user gate. 111 focused goal-frontier/replan/terminal tests pass at the exact head; Sign-off, builds, and dependency-review are green, and CI pytest was still in progress at review time.