[Cleanup] Remove 'Start Over' Button from Script Output

[chojuninengu]

Goal

Remove the 'Start Over' button from the final script generation screen (ScriptOutput.tsx).

Details

• The 'Start Over' button is redundant now that we are moving toward a persistent OS switcher in the header.
• Users can still manually clear their bucket from the cart UI if they wish to reset.

Tasks

• Remove the button at the bottom of src/components/script-output.tsx.
• Cleanup any logic associated with the full state reset if it's no longer used.