fix(module): add nested westech_r2/__init__.py for Frappe module resolution

Frappe get_module_path uses get_pymodule_path which expects
westech_r2.westech_r2 to be importable. The nested __init__.py
with __path__ redirection makes this work correctly.

westech_r2/westech_r2/__init__.py

@@ -0,0 +1,5 @@
+import os
+
+# Make westech_r2.westech_r2 resolve to the parent westech_r2 package
+# so Frappe's get_module_path("Westech R2") works correctly.
+__path__ = [os.path.dirname(os.path.dirname(__file__))]