feat(annotation): 添加标注项目文件快照功能

- 新增 LabelingProjectFile 模型用于存储标注项目的文件快照
- 在创建标注项目时记录关联的文件快照数据
- 更新查询逻辑以基于项目快照过滤文件列表
- 优化导出统计功能使用快照数据进行计算
- 添加数据库表结构支持项目文件快照关系

runtime/datamate-python/app/db/models/annotation_management.py

@@ -1,7 +1,7 @@
 """Tables of Annotation Management Module"""
 
-import uuid
-from sqlalchemy import Column, String, Boolean, TIMESTAMP, Text, Integer, JSON, ForeignKey
+import uuid
+from sqlalchemy import Column, String, Boolean, TIMESTAMP, Text, Integer, JSON, ForeignKey, UniqueConstraint, Index
 from sqlalchemy.sql import func
 
 from app.db.session import Base
@@ -34,7 +34,7 @@ class AnnotationTemplate(Base):
         """检查是否已被软删除"""
         return self.deleted_at is not None
     
-class LabelingProject(Base):
+class LabelingProject(Base):
     """标注项目模型"""
     
     __tablename__ = "t_dm_labeling_projects"
@@ -50,13 +50,33 @@ class LabelingProject(Base):
     updated_at = Column(TIMESTAMP, server_default=func.current_timestamp(), onupdate=func.current_timestamp(), comment="更新时间")
     deleted_at = Column(TIMESTAMP, nullable=True, comment="删除时间（软删除）")
     
-    def __repr__(self):
-        return f"<LabelingProject(id={self.id}, name={self.name}, dataset_id={self.dataset_id})>"
+    def __repr__(self):
+        return f"<LabelingProject(id={self.id}, name={self.name}, dataset_id={self.dataset_id})>"
     
     @property
-    def is_deleted(self) -> bool:
-        """检查是否已被软删除"""
-        return self.deleted_at is not None
+    def is_deleted(self) -> bool:
+        """检查是否已被软删除"""
+        return self.deleted_at is not None
+
+
+class LabelingProjectFile(Base):
+    """标注项目文件快照模型"""
+
+    __tablename__ = "t_dm_labeling_project_files"
+
+    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()), comment="UUID")
+    project_id = Column(String(36), nullable=False, comment="标注项目ID")
+    file_id = Column(String(36), nullable=False, comment="文件ID")
+    created_at = Column(TIMESTAMP, server_default=func.current_timestamp(), comment="创建时间")
+
+    __table_args__ = (
+        UniqueConstraint("project_id", "file_id", name="uk_project_file"),
+        Index("idx_project_id", "project_id"),
+        Index("idx_file_id", "file_id"),
+    )
+
+    def __repr__(self):
+        return f"<LabelingProjectFile(id={self.id}, project_id={self.project_id}, file_id={self.file_id})>"
 
 
 class AnnotationResult(Base):