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/db.py

@@ -843,6 +843,15 @@ POSTGRES_SCHEMA = (
     "error_text TEXT, "
     "created_at DOUBLE PRECISION, "
     "PRIMARY KEY(task_id, attempt_no))",
+    # 审计循环状态（audit loop）：task_id 单行主键；PG 新库一次
+    # 建齐，老库走 server/worker ensure（见 cloud/audit_loop.py）。
+    "CREATE TABLE IF NOT EXISTS task_audit_loop_state("
+    "task_id TEXT PRIMARY KEY, "
+    "round INTEGER, "
+    "passed_gates TEXT, "
+    "criteria TEXT, "
+    "last_decision TEXT, "
+    "updated_at DOUBLE PRECISION)",
     "CREATE TABLE IF NOT EXISTS projects("
     "id TEXT PRIMARY KEY, "
     "name TEXT, "