M2a：镜树域后端核心——树/节点/引文/归真/移栽全量 API 与 Kernel 完成回调（芽体固化/残答封存），8 用例钉死 PRD 场景 1/2/3/5/6/7/8

backend/app/models/__init__.py

@@ -19,6 +19,13 @@ 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.mirror_tree import (
+    Canonization,
+    Citation,
+    MirrorTree,
+    TreeNode,
+    TreeTransplant,
+)
 from app.models.memory import Memory, MemoryLink
 from app.models.personality import PersonalityProposal, PersonalityVersion
 from app.models.personality_emotion import CharacterEmotionState