fix: replace bare except with json.JSONDecodeError in app_settings.py

Changed bare except clause to catch json.JSONDecodeError specifically
when loading user settings JSON file. This ensures that:
- Only JSON parsing errors are caught (not SystemExit, KeyboardInterrupt)
- Debugging is easier as unexpected errors will propagate
- Follows Python best practices for exception handling

app/app_settings.py

@@ -21,7 +21,7 @@ class AppSettings():
             try:
                 with open(file) as f:
                     return json.load(f)
-            except:
+            except json.JSONDecodeError:
                 logging.error(f"The user settings file is corrupted: {file}")
                 return {}
         else: