feat: add contract template v3 api and legacy oss migration

fastapi_common/fastapi_common_storage/oss_path_utils.py

@@ -52,6 +52,24 @@ class OssPathUtils:
         prefix = f"{Region}/" if Region else ""
         return f"{prefix}rules/{RuleType}/{VersionNo}/validation_report.json"
 
+    @staticmethod
+    def BuildContractTemplateKey(
+        CategoryName: str,
+        TemplateCode: str,
+        FileRole: str,
+        FileName: str,
+    ) -> str:
+        """生成合同模板 object key。"""
+        ext = Path(FileName).suffix or ""
+        safe_category = OssPathUtils.BuildSafeFileStem(CategoryName or "uncategorized")
+        safe_template_code = OssPathUtils.BuildSafeFileStem(TemplateCode or "template")
+        safe_stem = OssPathUtils.BuildSafeFileStem(FileName)
+        safe_role = OssPathUtils.BuildSafeFileStem(FileRole or "file")
+        return (
+            f"contract-templates/{safe_category}/{safe_template_code}/"
+            f"{safe_role}__{safe_stem}{ext}"
+        )
+
     @staticmethod
     def BuildSafeFileStem(FileName: str) -> str:
         """生成适合放进 object key 的可读文件名主体。"""