fix(maf): harden stage-4 quality gate (P0/P1)

P0-1 migration: detect the same-named stage-3 execution_stage CHECK by sqltext (must contain rework + manager_review), SQLite rebuild / PG-MySQL drop+add, PG boolean default TRUE, validate_schema checks constraint content + seat_tasks status CHECK/unique/FKs; tests start from a real stage-3 schema.

P0-2: a missing/invalid manager review (timeout/exception/empty/invalid JSON/missing per-seat decision) is never an acceptance - system rework under the cap, contract fallback (reassign/controlled_gap/ask_user) afterwards, source=system events.

P0-3: unaccepted deliveries are isolated from the fact ledger, cross-review and final report (deferred merge, delivery_json envelope, accepted_task_results in checkpoint, accepted-only synthesis, no turn_results fallback).

P0-4: seat-task init is atomic get-or-create over the full expected set; recovery fills missing tasks without overwriting frozen contracts; quality gate blocks missing required tasks.

P1: zero config values honoured; duplicate detection persists SHA-256 conclusion digests in history (survives restarts); findings never satisfy evidence, evidence_refs must resolve to trusted ledger refs (unverified_evidence_ref); conversation SSE projection tests added and manager/finalizer messages are no longer mislabelled as seat.delivery.submitted.

frontend-web/docs/microsoft-agent-framework-多智能体会商-实施计划.md

@@ -643,3 +643,38 @@ maf-roundtable/conversation/
 - The final plan is Pydantic-validated and allowlisted before it is checkpointed. Invalid JSON, illegal intent or seat, missing convergence, manager failure, and timeout all finish on the clarification branch; they do not create expert threads or start expert/tool work.
 - A conversation initially persists and binds the manager only. After a valid decision, only `selected_seat_agent_ids` are added to the participant store and receive internal threads.
 - Every non-clarification route, including `group_chat`, starts at the same manager dispatch node. Group speakers are limited to the verified selected seats; static candidate configuration cannot bypass the plan.
+
+---
+
+## 阶段 4 实施记录（当前代码基线）
+
+本轮完成阶段 4（R3-Q：席位任务合同、总控验收、打回/改派/受控缺口、阶段质量闸门）的服务端实现。范围仅限 V2 structured 派活（`dispatch_contract_enabled` 且 `quality_gate_enabled`）；旧 DeerFlow、旧 roundtable、AI 写作、group_chat 与 quality 关闭的 V2 路径行为不变。
+
+### 纯策略层（`app/maf_roundtable/quality_contracts.py`，无 I/O、无 SDK）
+
+- `MafTaskContract`：objective / expected_deliverable / acceptance_criteria / required / max_rework_attempts（默认 2）/ fallback_policy（`reassign_then_gap` / `controlled_gap` / `ask_user`），由校验后的派发 assignment 服务端冻结。
+- 确定性检查 `check_delivery_deterministic`：empty_content、schema_invalid、missing_conclusion、below_min_length、missing_evidence、duplicate_content；任一失败即不可 accept（总控模型自评不是验收证据）。
+- 总控验收 schema `MafManagerReviewOutput`（decision ∈ accept / return_for_rework / reassign / ask_user / controlled_gap + reason + revision_requirements），`finalize_review_decision` 服务端终审：确定性失败永不 accept；返工受合同上限约束；改派受 `max_reassignments` 约束；耗尽后只能 `controlled_gap`（带风险标记）或 `ask_user` 暂停，绝不伪装成功；总控输出缺失/非法时确定性降级。
+
+### 持久化
+
+- 新表 `maf_roundtable_seat_tasks`（`model.py` + `seat_tasks.py` + store facade 注册）：task_key 稳定（`NN:agent_id`），改派只变 `agent_id` 不新建任务；`(run_id, task_key)` 唯一；状态机 CHECK（assigned/delivering/submitted/manager_review/accepted/rework/reassigned/exhausted/controlled_gap）。
+- `maf_roundtable_seat_runs.execution_stage` 闭合枚举新增 `rework`、`manager_review`（seat_runs 常量 + ORM CHECK + 迁移脚本同步）。
+- 迁移脚本 `scripts/migrate_maf_roundtable_stage4.py`（建表 + SQLite 重建 seat_runs 以放宽 CHECK，PG/MySQL drop+add，幂等，`validate_schema`）。
+
+### 执行器与接线
+
+- `QualitySeatTasksExecutor`（id=`quality_seat_tasks`）替换 V2 structured 的席位 fan-out：有界质量轮（初稿 + 最多 2 次返工 + 每次改派 1 轮），每轮「交付（复用 SeatExecutor，静默 ctx 防消息重入图）→ 确定性检查 → 批处理总控验收 → 服务端终审落库」，`ask_user` 置 `waiting_input`；改派席位须为服务端候选且未占用其他任务（一个席位同时只承担一个任务，避免四元组冲突）。
+- `QualityGateExecutor`（id=`quality_gate`）：所有 required 任务达到 accepted / controlled_gap 终态才放行（`passed` / `passed_with_gaps`）；非终态 required 任务确定性阻塞（硬失败安全网）；`waiting_input` 路由到 `WaitingInputTerminalExecutor`（不跑 cross_review/finalizer）。
+- 最终报告：受控缺口注入综合 prompt 的「风险/待补信息」章节并逐条要求不得写成已验证事实；`final_result.quality_decision` 有缺口即为 `controlled_gap`，`final_result.controlled_gaps` 可追溯。
+- 配置：`quality_gate_enabled`（默认 True，V2 会话可用 `maf_v2.quality_gate_enabled` 显式关闭）、`max_rework_attempts`、`max_reassignments`、`min_delivery_chars`、`min_delivery_evidence`、`default_fallback_policy`。
+- 事件：`seat.delivery.submitted`、`manager.review.decision`（带 task_key/attempt/source）、`seat.rework.assigned`、`seat.reassigned`、`stage.quality_gate`；conversation 投影白名单与安全键已扩展。
+
+### 测试
+
+- `tests/test_maf_quality_contracts.py`（34 例纯策略：合同冻结、确定性检查、验收解析、终审规则矩阵）。
+- `tests/test_maf_phase4_quality_gate.py`（6 例 Runner 级端到端：好交付接受、短答→2 返工→1 改派→受控缺口（含 DB/事件/最终报告断言）、ask_user→waiting_input、质量闸门阻塞、缺失验收的确定性降级、事件落库）。
+- `tests/test_maf_migration_stage4.py`（3 例迁移：建表+CHECK 放宽、幂等、旧数据保留、新阶段可写入）。
+- 回归：全量 MAF 测试 459 通过；`ruff check` 全绿。
+
+仍按阶段 5/8 前置条件保持阻塞：真实 UAT 写入系统、最小权限凭据、外部核验 API、补偿协议和生产 `MAF_ACTION_SECRET_KEY`。前端对话页的质量反馈（派活卡显示尝试次数、「总控审核中」、打回/改派/缺口卡片、席位条状态区分）属阶段 7 的前端工作，尚未实施。