fix(business): 唯一键冲突重试改为审计上下文内循环，单条审计无递归

三处 create（业务/发货/回款）的 return _retry_create 是吞异常后正常
退出：外层审计把已回滚的首次尝试记成 success（假成功），重入整个
create_* 违反 audit_service「不支持嵌套」约定，且 _NO_RETRY 死常量
导致持续冲突时无界递归至 RecursionError。改为 audit 内 for 循环
（上限 _NO_RETRY），rollback 后重新锁行与取号，成功/最终失败各恰好
一条审计。新增集成用例锁定两条路径的日志增量。

Co-Authored-By: Claude Code <noreply@anthropic.com>

backend/app/services/business_service.py

@@ -301,58 +301,54 @@ def create_business(
         if payload.assistant_personnel_id is not None:
             _ensure_personnel_active(session, payload.assistant_personnel_id, "协助")
 
-        try:
-            business = Business(
-                business_no=_generate_no(session),
-                customer_id=payload.customer_id,
-                business_date=payload.business_date,
-                status=BUSINESS_STATUS_ACTIVE,
-                owner_personnel_id=payload.owner_personnel_id,
-                assistant_personnel_id=payload.assistant_personnel_id,
-                is_special=payload.is_special,
-                special_note=payload.special_note,
-                remark=payload.remark,
-            )
-            business_repository.create(session, business)
-            business_repository.replace_items(
-                session, business.id, _build_item_rows(business.id, payload.items)
-            )
-            _recalc_totals(session, business)
-            business_repository.add_status_log(
-                session,
-                BusinessStatusLog(
-                    business_id=business.id,
-                    old_status=BUSINESS_STATUS_ACTIVE,
-                    new_status=BUSINESS_STATUS_ACTIVE,
-                    operator_id=operator.id,
-                    operator_name=operator.username,
-                ),
-            )
-            customer = customer_repository.get_by_id(session, business.customer_id)
-            out = _to_out((business, customer.company_name if customer else None, None, None))
-            session.commit()
-        except IntegrityError as exc:
-            session.rollback()
-            if _is_duplicate_entry(exc):
-                # 编号生成的残余竞态：唯一键兜底重试一次（防无限重试掩盖死锁）
-                return _retry_create(session, payload, operator=operator, meta=meta)
-            raise
+        # 编号唯一键冲突的重试整体收在审计上下文内：rollback 后同一事务重来，
+        # 成功/最终失败各只记一条审计（吞异常 return 会被记成假成功，重入
+        # 整个 create_* 则违反「不支持嵌套」约定）；上限 _NO_RETRY 防无限重试
+        # 掩盖死锁类缺陷。审计摘要预取的是首次编号——重试成功时入库编号见
+        # 应用日志（AuditRecord frozen，不回填）。
+        for attempt in range(_NO_RETRY + 1):
+            try:
+                business = Business(
+                    business_no=_generate_no(session),
+                    customer_id=payload.customer_id,
+                    business_date=payload.business_date,
+                    status=BUSINESS_STATUS_ACTIVE,
+                    owner_personnel_id=payload.owner_personnel_id,
+                    assistant_personnel_id=payload.assistant_personnel_id,
+                    is_special=payload.is_special,
+                    special_note=payload.special_note,
+                    remark=payload.remark,
+                )
+                business_repository.create(session, business)
+                business_repository.replace_items(
+                    session, business.id, _build_item_rows(business.id, payload.items)
+                )
+                _recalc_totals(session, business)
+                business_repository.add_status_log(
+                    session,
+                    BusinessStatusLog(
+                        business_id=business.id,
+                        old_status=BUSINESS_STATUS_ACTIVE,
+                        new_status=BUSINESS_STATUS_ACTIVE,
+                        operator_id=operator.id,
+                        operator_name=operator.username,
+                    ),
+                )
+                customer = customer_repository.get_by_id(session, business.customer_id)
+                out = _to_out((business, customer.company_name if customer else None, None, None))
+                new_id, new_no = business.id, business.business_no  # 固化：commit 后不碰 ORM
+                session.commit()
+                break
+            except IntegrityError as exc:
+                session.rollback()
+                if _is_duplicate_entry(exc) and attempt < _NO_RETRY:
+                    continue
+                raise
 
-        logger.info("创建业务 | business_id=%s | no=%s", business.id, business.business_no)
+        logger.info("创建业务 | business_id=%s | no=%s", new_id, new_no)
         return out
 
 
-def _retry_create(
-    session: Session,
-    payload: BusinessCreateIn,
-    *,
-    operator: User,
-    meta: RequestMeta | None,
-) -> BusinessOut:
-    """编号撞唯一键后的单次重试（防无限重试掩盖死锁类缺陷）。"""
-    return create_business(session, payload, operator=operator, meta=meta)
-
-
 def update_business(
     session: Session,
     business_id: int,