chore: fix tests_on_pr

Author: ycexiao

src/diffpy/__init__.py

@@ -0,0 +1,14 @@
+#!/usr/bin/env python
+##############################################################################
+#
+# (c) 2026 The Trustees of Columbia University in the City of New York.
+# All rights reserved.
+#
+# File coded by: Billinge Group members and community contributors.
+#
+# See GitHub contributions for a more detailed list of contributors.
+# https://github.com/diffpy/diffpy.apps/graphs/contributors
+#
+# See LICENSE.rst for license information.
+#
+##############################################################################