fix: explicitly include src package and subpackages in setup.py

setup.py

@@ -5,6 +5,6 @@ from setuptools import find_packages, setup
 setup(
     name="voice-tools",
     version="0.1.0",
-    packages=find_packages(),
+    packages=find_packages(include=["src", "src.*"]),
     python_requires=">=3.10",
 )