feat(api+app): 对话阶段化、回忆录流水线与客户端会话体验

- DB: segments 用户输入文本（Alembic 0002）
- Chat: 阶段检测/阶段提示/回复限制，编排与访谈/画像 prompts 调整
- Memoir: 忠实度检查 agent，叙事与分类等链路更新
- Core: agent 日志、Alembic 启动、LangChain/日志/配置等
- Story: time_hints；Memory 检索与相关测试
- Expo: 助手头像、会话页与消息拆分、实时会话与文案/i18n
- Docs/scripts/tests: 迁移脚本、LLM JSON/记忆检索文档、新增单测

api/app/features/payment/order_service.py

@@ -115,7 +115,7 @@ class PaymentOrderService:
             except Exception as e:
                 order.status = "failed"
                 await self._db.flush()
-                logger.exception("微信支付客户端初始化失败: %s", e)
+                logger.exception("微信支付客户端初始化失败: {}", e)
                 raise HTTPException(status_code=503, detail=f"微信支付暂不可用: {e!s}")
 
         try:
@@ -145,14 +145,14 @@ class PaymentOrderService:
         except Exception as e:
             order.status = "failed"
             await self._db.flush()
-            logger.exception("创建支付订单异常: %s", e)
+            logger.exception("创建支付订单异常: {}", e)
             raise HTTPException(
                 status_code=500, detail=f"创建支付订单异常: {type(e).__name__}: {e!s}"
             )
 
         await self._db.commit()
         logger.info(
-            "订单创建成功: order_no=%s, payment_method=%s, amount_fen=%s",
+            "订单创建成功: order_no={}, payment_method={}, amount_fen={}",
             order_no,
             payment_method,
             amount_fen,
@@ -168,10 +168,10 @@ class PaymentOrderService:
         result = await self._db.execute(select(Order).where(Order.id == out_trade_no))
         order = result.scalar_one_or_none()
         if order is None:
-            logger.warning("支付回调: 订单不存在 %s", out_trade_no)
+            logger.warning("支付回调: 订单不存在 {}", out_trade_no)
             return
         if order.status == "paid":
-            logger.info("支付回调: 订单已处理过 %s", out_trade_no)
+            logger.info("支付回调: 订单已处理过 {}", out_trade_no)
             return
         now = utc_now()
         order.status = "paid"
@@ -191,14 +191,14 @@ class PaymentOrderService:
                 user.subscription_expires_at = now + timedelta(days=duration_days)
             user.subscription_type = order.plan_id
             logger.info(
-                "用户 %s 订阅已升级为 %s，到期: %s",
+                "用户 {} 订阅已升级为 {}，到期: {}",
                 user.id,
                 order.plan_id,
                 user.subscription_expires_at,
             )
         await self._db.commit()
         logger.info(
-            "支付成功处理完成: 订单 %s, 第三方交易号 %s", out_trade_no, trade_no
+            "支付成功处理完成: 订单 {}, 第三方交易号 {}", out_trade_no, trade_no
         )
 
     async def handle_wechat_notify(self, headers: dict, body: str) -> dict: