Chore and Feature Updates

This pull request includes several updates to improve the app. First, we added .sonar_lock and report-task.txt to the version control for better management of the project's code quality. Then, we added an example environment variable for the app URL and loaded the variables using dotenv to improve the configuration process. Finally, we added comments and functionality to prevent the re-downloading of a video that has already been downloaded. These updates enhance the app's functionality and maintainability.