feat(agent_assets): 添加规则版本送审时的命名副本创建逻辑

当提交的版本与当前工作版本不同时，自动创建命名副本：
- 新增 _create_named_working_copy_for_review 方法处理送审时的版本复制
- 支持将工作版本快照复制为指定版本进行送审
- 新增 AgentAssetSpreadsheetChangeRecordRead schema
- API 端点新增 /rules/{id}/spreadsheet-versions/{version}/change-records 接口

server/src/app/schemas/agent_asset.py

@@ -128,6 +128,16 @@ class AgentAssetVersionCompareRead(BaseModel):
     cell_changes: list[AgentAssetSpreadsheetDiffCellRead] = Field(default_factory=list)
 
 
+class AgentAssetSpreadsheetChangeRecordRead(BaseModel):
+    actor: str
+    changed_at: datetime
+    summary: str
+    sheet_changes: list[AgentAssetSpreadsheetDiffSheetRead] = Field(default_factory=list)
+    cell_changes: list[AgentAssetSpreadsheetDiffCellRead] = Field(default_factory=list)
+    changed_sheet_count: int = 0
+    changed_cell_count: int = 0
+
+
 class AgentAssetVersionRead(BaseModel):
     model_config = ConfigDict(from_attributes=True)