Yes, your license will always be valid and you will have access to all the premium features of your current version of RunJS. The one year period only relates to updates.
After one year you'll have the option to renew your license to continue getting updates. You will still have access to all the premium features on your current version of RunJS.
Yes. To do this open the 'Manage License' modal from the app menu and click 'Deactivate License'. This will free up your license for use on another computer.
A full list of shortcuts can be found in the docs.
If you don't see the menu bar, it may have been accidentally toggled it off. You can bring it back by pressing Alt.
You can disable hiding the menu bar with Alt by selecting 'Toggle Menu Bar' from the 'View' menu.