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/memoir/service.py

@@ -52,7 +52,7 @@ class MemoirService:
         self._object_storage = object_storage
 
     async def get_evidence(self, user_id: str, query: str, *, top_k: int = 10) -> dict:
-        """通过 MemoryService 获取检索证据（章节生成时优先使用）。"""
+        """通过 MemoryService → HybridRetriever 获取证据（含向量时与 Celery 的 FTS-only 路径不同）。"""
         if self._memory is None:
             return {
                 "relevant_chunks": [],
@@ -66,7 +66,7 @@ class MemoirService:
         cleaned = False
         for rec in getattr(ch, "images", None) or []:
             if rec and is_image_permanently_unavailable(rec):
-                logger.info("清理不可用配图: chapter=%s, image=%s", ch.id, rec.id)
+                logger.info("清理不可用配图: chapter={}, image={}", ch.id, rec.id)
                 await self._db.delete(rec)
                 cleaned = True
         if cleaned:
@@ -284,7 +284,7 @@ class MemoirService:
             )
             if enqueued:
                 triggered.append(ch.id)
-                logger.info("触发生成章节封面(asset): chapter=%s", ch.id)
+                logger.info("触发生成章节封面(asset): chapter={}", ch.id)
         return {"triggered": triggered}
 
     async def mark_memoir_read(self, user_id: str) -> dict: