M3a：息壤三级记忆域——归真触发提取管线/白名单明忆/重忆确认/正影版本链/删除墓碑/双通道召回注入，退役旧记忆-抽取-反思-大周天-演化管线（迁移 004，验收 7 用例）

backend/app/repositories/characters.py

@@ -4,7 +4,7 @@ from sqlalchemy import func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.character import Character
-from app.models.memory import Memory
+from app.models.xirang import Memory
 
 
 async def get_active_character(session: AsyncSession, owner_scope: str) -> Character | None:
@@ -98,7 +98,7 @@ async def count_memories(session: AsyncSession, character_id: str) -> int:
         await session.execute(
             select(func.count())
             .select_from(Memory)
-            .where(Memory.character_id == character_id, Memory.deleted_at.is_(None))
+            .where(Memory.character_id == character_id, Memory.status != "tombstoned")
         )
     ).scalar_one()
     return int(total or 0)