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/server.py

@@ -64,6 +64,7 @@ from cloud.agent_def import parse_agent_tool_approvals_column as _parse_tool_app
 from cloud.agent_def import parse_agent_tools_column as _parse_tools_col
 from cloud.agent_def import resolve_registry_agent as _resolve_agent
 from cloud.attempts import ensure_attempts_table as _ensure_attempts
+from cloud.audit_loop import ensure_audit_loop_table as _ensure_audit_loop
 from cloud.auth import ROLES as _MEMBER_ROLES
 from cloud.auth import AuthStore
 from cloud.coordinator import parse_parts as _coord_parse_parts
@@ -1725,6 +1726,7 @@ def init_db(db_path):
             _ensure_task_checkpoints_table(conn)
             _ensure_task_steps_table(conn)
             _ensure_attempts(conn)
+            _ensure_audit_loop(conn)
             conn.commit()
             return
         conn.execute(
@@ -1762,6 +1764,7 @@ def init_db(db_path):
         _ensure_task_checkpoints_table(conn)
         _ensure_task_steps_table(conn)
         _ensure_attempts(conn)
+        _ensure_audit_loop(conn)
         ensure_kill_requests_table(conn)
         # 常驻监听表（P0 S3 的 SQLite 侧）：启动时建一次，
         # 热路径（claim/run_due/批量）不再逐条 ensure，