Add bytecode cleanup to postinst before building wheel

Remove stale .pyc files and __pycache__ directories before installing
the sensorpajen package to ensure Python rebuilds bytecode fresh.

This should prevent cached bytecode issues from old syntax errors.

debian/postinst

@@ -64,6 +64,9 @@ case "$1" in
         # Install sensorpajen package itself
         echo "Installing sensorpajen application..."
         cd /opt/sensorpajen
+        # Clean up any stale bytecode before building wheel
+        find . -name "*.pyc" -delete
+        find . -name "__pycache__" -type d -delete
         venv/bin/pip install --no-deps . || {
             echo "Error: Failed to install sensorpajen package"
             exit 1