M1：镜生域后端闭环——灵胚/照心试演/启镜原子闸门/执镜关系/命台租约/魂籍签名导出/死亡冷静期（迁移 001，测试 7 用例）

backend/app/models/__init__.py

@@ -16,6 +16,7 @@ from app.models.governance import (
 )
 from app.models.idempotency import IdempotencyKey
 from app.models.imports import CharacterImportJob, ImportItem
+from app.models.jingsheng import Custodianship, EmbryoDraft, IdentityRecord, RuntimeSeat
 from app.models.lorebook import Lorebook, LorebookEntry
 from app.models.mcp_servers import McpServer
 from app.models.memory import Memory, MemoryLink