Backup Jobs State Persistence

As a user, I want to the system to save my configured backup jobs (Name, Source, Target, Type) into a jobs.json file, So that I do not have to reconfigure my backup plans every time I close and reopen the application.

Given the user creates or modifies a backup job in the menu,
When the action is confirmed,
Then the job details are serialized and saved to the jobs.json file.

Given the application boots up,
When it reads the jobs.json file,
Then it successfully parses the JSON and loads the saved jobs into the application memory.

Given the user attempts to create a new job,
When the strict limit of 5 configured jobs is already reached,
Then the system blocks the creation and displays a clear error message respecting the 5-job maximum constraint.