M2b：删除旧 chat 体系——线性会话/叩心/情绪/纪念日模型与页面退役（迁移 003 双向验证），runs 去会话外键，测试全量修剪

backend/app/models/__init__.py

@@ -3,7 +3,6 @@
 from app.models.big_cycle import BigCycle
 from app.models.candidates import MemoryCandidate, ProfileCandidate
 from app.models.character import Character
-from app.models.chat import ChatMessage, ChatSession
 from app.models.drive import CuriosityQuestion, ExploratorySubgoal
 from app.models.evolution import EvolutionCandidate
 from app.models.governance import (
@@ -28,12 +27,10 @@ from app.models.mirror_tree import (
 )
 from app.models.memory import Memory, MemoryLink
 from app.models.personality import PersonalityProposal, PersonalityVersion
-from app.models.personality_emotion import CharacterEmotionState
 from app.models.rbac import Permission, Role, RolePermission, UserRole
 from app.models.runtime import Event, Run
 from app.models.safety import AuditEvent, PendingConfirmationRecord
 from app.models.skills import Skill
-from app.models.time_anniversary import TimeAnniversary
 from app.models.user import User
 from app.models.world import CharacterWorldEntity, WorldRelation
 
@@ -42,11 +39,8 @@ __all__ = [
     "AuditEvent",
     "BigCycle",
     "Character",
-    "CharacterEmotionState",
     "CharacterImportJob",
     "CharacterWorldEntity",
-    "ChatMessage",
-    "ChatSession",
     "CuriosityQuestion",
     "Event",
     "EvolutionCandidate",
@@ -72,7 +66,6 @@ __all__ = [
     "RolePermission",
     "Run",
     "Skill",
-    "TimeAnniversary",
     "User",
     "UserRole",
     "WorldEntity",