fixed bug: programs could not be installed if the list of installed programs…

src/window.py

@@ -227,17 +227,17 @@ class EepmPlayGuiWindow(Adw.ApplicationWindow):
             )
 
     def get_install_remove_lists(self):
-        if not (self.installed_apps and self.rows):
-            return [], []
+        installed_apps = self.installed_apps or []
+        rows = self.rows or {}
 
         to_install = [
-            app_name for app_name, row in self.rows.items()
-            if row.checkbox.get_active() and app_name not in self.installed_apps
+            app_name for app_name, row in rows.items()
+            if row.checkbox.get_active() and app_name not in installed_apps
         ]
 
         to_remove = [
-            app_name for app_name, row in self.rows.items()
-            if not row.checkbox.get_active() and app_name in self.installed_apps
+            app_name for app_name, row in rows.items()
+            if not row.checkbox.get_active() and app_name in installed_apps
         ]
 
         return to_install, to_remove