refactor(api): TOML 配置 SSOT、统一错误契约、Auth/事务加固与可观测性 (#33)

配置 SSOT（TOML + .env）
统一错误契约
Auth 与事务边界
Redis / Celery 可靠性:业务 Redis（DB/0）与 Celery broker/backend（DB/1）显式拆分；连接池、sync client
可观测性（OpenTelemetry + LGTM）

api/app/features/conversation/ws/profile_collector.py

@@ -2,6 +2,7 @@
 
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.core.db import transactional
 from app.features.user.models import User
 
 
@@ -37,17 +38,21 @@ async def apply_extracted_profile(user: User, extracted: dict, db: AsyncSession)
     """将提取到的资料信息保存到用户模型"""
     changed = False
     if "birth_year" in extracted and not user.birth_year:
-        user.birth_year = extracted["birth_year"]
         changed = True
     if "birth_place" in extracted and not user.birth_place:
-        user.birth_place = extracted["birth_place"]
         changed = True
     if "grew_up_place" in extracted and not user.grew_up_place:
-        user.grew_up_place = extracted["grew_up_place"]
         changed = True
     if "occupation" in extracted and not user.occupation:
-        user.occupation = extracted["occupation"]
         changed = True
     if changed:
-        await db.commit()
+        async with transactional(db):
+            if "birth_year" in extracted and not user.birth_year:
+                user.birth_year = extracted["birth_year"]
+            if "birth_place" in extracted and not user.birth_place:
+                user.birth_place = extracted["birth_place"]
+            if "grew_up_place" in extracted and not user.grew_up_place:
+                user.grew_up_place = extracted["grew_up_place"]
+            if "occupation" in extracted and not user.occupation:
+                user.occupation = extracted["occupation"]
         await db.refresh(user)