Single Job Execution from the Interactive Menu

As a user, I want to select and execute a single specific backup job from the interactive menu, So that I can run an individual backup without triggering the others and without using the command line.

Given the user is on the main menu,
When they select "Execute a specific job" and input a valid job index (e.g., 2),
Then only Job 2 is executed.

Given the user is prompted to select a job to execute,
When they input an empty slot or an invalid index,
Then the application displays an error and returns to the menu without crashing.