chore: scaffold Mudfish VPN decky plugin

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_smoke.py

@@ -0,0 +1,12 @@
+import unittest
+
+import mudfish_decky
+
+
+class SmokeTest(unittest.TestCase):
+    def test_package_imports(self):
+        self.assertTrue(hasattr(mudfish_decky, "__name__"))
+
+
+if __name__ == "__main__":
+    unittest.main()