fix: bounded audit loop (deterministic gates only, 3 pushbacks, escalate)

Audit loop engine (cloud/audit_loop.py): Finding/PushbackPacket/LoopState pure functions; deterministic gates only, subjective -> needs_review; packet completeness enforced; standards-weakening -> escalate; regression and missing-gate checks enforce full re-run; MAX_PUSHBACKS=3, round>=3 -> escalate. Persistence in new single-row task_audit_loop_state (attempts DDL pattern: module CREATE_TABLE_SQL + db.py POSTGRES_SCHEMA + migrations list + server init + worker ensure); task_attempts NOT reused (attempt_no PK collision) and task_followups NOT reused (user messages). Worker.audit_loop_evaluate is the explicit opt-in hook (task audit_loop field only, no env switch, never called by run_one); escalate audits worker_audit_loop_escalated; corrupted/missing count fail-closes to escalate.

cloud/worker.py

@@ -143,6 +143,10 @@ from cloud.attempts import build_resume_preamble as _resume_preamble
 from cloud.attempts import ensure_attempts_table as _ensure_attempts
 from cloud.attempts import latest_attempt as _latest_attempt
 from cloud.attempts import record_attempt as _record_attempt
+from cloud.audit_loop import ensure_audit_loop_table as _ensure_audit_loop
+from cloud.audit_loop import evaluate as _audit_loop_evaluate
+from cloud.audit_loop import load_loop_state as _audit_loop_load
+from cloud.audit_loop import save_loop_state as _audit_loop_save
 from cloud.auth import AuthStore
 from cloud.coordinator import build_report as _coord_build_report
 from cloud.coordinator import DEFAULT_POLL_INTERVAL as _COORD_POLL_INTERVAL
@@ -1792,6 +1796,101 @@ class Worker:
             except Exception:
                 pass
 
+    def audit_loop_evaluate(self, task, gate_results, findings=None,
+                            fixed=None):
+        """有界审计循环的显式入口（默认关闭，绝不由 run_one 自动调用）。
+
+        启用条件二选一中只选其一：任务字典含 audit_loop 真值。
+        没有 env 开关——全局 env 会让所有任务悄悄启用循环，本方法
+        刻意拒绝它。开关关闭时返回 enabled=False 且不碰数据库，
+        run_one、auto_resume、协调员、goal 断点行为逐字节不变。
+
+        本方法不改任务状态、不重排、不调 runner、不重新决策：
+        它只给决策——pass（放行）、pushback（调用方持 packet 重排
+        任务，packet 里有失败项、证据、复现、验收标准）、escalate
+        （调用方置任务 failed/needs_review，不再自动循环）、
+        needs_review（主观发现，走人工）、off（未启用）。
+        升级时记 worker_audit_loop_escalated 审计（best-effort，
+        审计失败不改决策）。轮次存在 task_audit_loop_state 单行表，
+        计数损坏时 fail-closed 到 escalate，绝不默认循环。
+        调用参数非法（空证据、空门集、非法门结果）时同样
+        fail-closed 到 escalate，不进循环。
+        gate_results 必须含本轮全部已跑的门；上一轮通过的门本轮
+        缺跑或变失败时，引擎按 gate_missing / regression 升级或推回。
+        """
+        task = task if isinstance(task, dict) else {}
+        if not task.get("audit_loop"):
+            return {"enabled": False, "decision": "off", "packet": None,
+                    "new_state": None, "reason": None}
+        task_id = task.get("id")
+        project_id = task.get("project_id")
+        try:
+            conn = _db_connect(self.db_path)
+        except Exception as exc:
+            # 连库都连不上：无法持久化轮次，fail-closed 到升级。
+            try:
+                self._audit(project_id, "worker_audit_loop_escalated",
+                            "%s reason=state_unreadable error=%s"
+                            % (task_id, exc))
+            except Exception:
+                pass
+            return {"enabled": True, "decision": "escalate", "packet": None,
+                    "new_state": None, "reason": "state_unreadable"}
+        try:
+            _ensure_audit_loop(conn)
+            state, corrupted, error = _audit_loop_load(conn, task_id)
+            if corrupted:
+                try:
+                    self._audit(
+                        project_id, "worker_audit_loop_escalated",
+                        "%s reason=count_corrupted error=%s"
+                        % (task_id, error))
+                except Exception:
+                    pass
+                return {"enabled": True, "decision": "escalate",
+                        "packet": None, "new_state": None,
+                        "reason": "count_corrupted"}
+            decision = _audit_loop_evaluate(
+                state, task_id, gate_results, findings=findings,
+                fixed=fixed)
+            if decision["new_state"] is not None:
+                _audit_loop_save(conn, decision["new_state"])
+            conn.commit()
+        except Exception as exc:
+            # 评估或写状态失败：轮次不可信，fail-closed 到升级。
+            try:
+                conn.rollback()
+            except Exception:
+                pass
+            try:
+                self._audit(project_id, "worker_audit_loop_escalated",
+                            "%s reason=evaluate_failed error=%s"
+                            % (task_id, exc))
+            except Exception:
+                pass
+            return {"enabled": True, "decision": "escalate", "packet": None,
+                    "new_state": None, "reason": "evaluate_failed"}
+        finally:
+            try:
+                conn.close()
+            except Exception:
+                pass
+        if decision["decision"] == "escalate":
+            try:
+                self._audit(
+                    project_id, "worker_audit_loop_escalated",
+                    "%s reason=%s round=%s"
+                    % (task_id, decision["reason"], decision["round"]))
+            except Exception:
+                pass
+        result = dict(decision)
+        result["enabled"] = True
+        if result.get("packet") is not None:
+            result["packet"] = result["packet"].to_dict()
+        if result.get("new_state") is not None:
+            result["new_state"] = result["new_state"].to_dict()
+        return result
+
     def _notify_task_finished(self, task_id, project_id, event_type,
                               error=None):
         """任务终态推送：best-effort，绝不因通知失败影响任务状态。