Feature/memory work (#61)

* refactor(conversation): separate service and repository layers for conversation module

- Split ConversationService and repository/UnitOfWork layers
- Service layer now only handles business logic and orchestration
- Repository layer handles all direct database operations
- UnitOfWork encapsulates transactional operations for messages
- Ensured all public methods have clear English docstrings with arguments, return values, and exceptions

* feat(memory): implement work memory endpoints and services

- Added API routes for conversation count, conversation list, messages, and detail.
- Integrated ConversationService for database queries and LLM-based summary generation.

* feat(memory): implement work memory endpoints and services

- Added API routes for conversation count, conversation list, messages, and detail.
- Integrated ConversationService for database queries and LLM-based summary generation.

* feat(workflow): fix issues causing workflow failures

if-else None value error
knowledge empty list rerank
end node output none node value
assigner input none value

* feat(memory): convert memory file creation time to timestamp and include title and first-line fields in file type

* fix(memory): fix serialization output and default value issues

* fix(workflow): fix issue with hybrid search logic in knowledge retrieval node

api/app/models/conversation_model.py

@@ -3,6 +3,7 @@
 """
 import uuid
 import datetime
+
 from sqlalchemy import Column, String, DateTime, ForeignKey, Boolean, Integer, Text, JSON
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import relationship
@@ -25,56 +26,69 @@ class Conversation(Base):
     __tablename__ = "conversations"
 
     id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, index=True)
-    
+
     # 关联信息
     app_id = Column(UUID(as_uuid=True), ForeignKey("apps.id"), nullable=False, comment="应用ID")
     workspace_id = Column(UUID(as_uuid=True), ForeignKey("workspaces.id"), nullable=False, comment="工作空间ID")
     user_id = Column(String, nullable=True, comment="用户ID（外部系统）")
-    
+
     # 会话信息
     title = Column(String(255), comment="会话标题")
     summary = Column(Text, comment="会话摘要")
-    
+
     # 会话类型：True=草稿会话（使用草稿配置），False=发布会话（使用发布配置）
     is_draft = Column(Boolean, default=True, nullable=False, comment="是否为草稿会话")
-    
+
     # 配置快照：保存创建会话时的完整配置，用于审计和问题追溯
     config_snapshot = Column(JSON, comment="配置快照（Agent配置、模型配置等）")
-    
+
     # 统计信息
     message_count = Column(Integer, default=0, comment="消息数量")
-    
+
     # 状态
     is_active = Column(Boolean, default=True, nullable=False, comment="是否活跃")
-    
+
     # 时间戳
     created_at = Column(DateTime, default=datetime.datetime.now, comment="创建时间")
     updated_at = Column(DateTime, default=datetime.datetime.now, onupdate=datetime.datetime.now, comment="更新时间")
-    
+
     # 关联关系
     app = relationship("App", back_populates="conversations")
     workspace = relationship("Workspace")
     messages = relationship("Message", back_populates="conversation", cascade="all, delete-orphan")
 
 
+class ConversationDetail(Base):
+    __tablename__ = "conversation_details"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, index=True)
+    conversation_id = Column(UUID(as_uuid=True), ForeignKey("conversations.id"))
+
+    theme = Column(String, comment="会话主题")
+    theme_intro = Column(String, comment="主题介绍")
+    summary = Column(String, comment="会话摘要")
+    takeaways = Column(JSON, comment="会话要点")
+    info_score = Column(Integer, comment="会话信息量评分")
+
+
 class Message(Base):
     """消息表"""
     __tablename__ = "messages"
 
     id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, index=True)
-    
+
     # 关联信息
     conversation_id = Column(UUID(as_uuid=True), ForeignKey("conversations.id"), nullable=False, comment="会话ID")
-    
+
     # 消息内容
     role = Column(String(20), nullable=False, comment="角色: user/assistant/system")
     content = Column(Text, nullable=False, comment="消息内容")
-    
+
     # 元数据（避免使用 metadata 保留字）
     meta_data = Column(JSON, comment="消息元数据（如模型、token使用等）")
-    
+
     # 时间戳
     created_at = Column(DateTime, default=datetime.datetime.now, comment="创建时间")
-    
+
     # 关联关系
     conversation = relationship("Conversation", back_populates="messages")