Add resest function and update import to include overwrite, append end and prepend options

[khush3e]

1. The New Reset Button

The Problem:
Before this, if you wanted a clean slate, you had to either manually delete every single line or do a full "hard reload" of the website. It was a bit of a workflow killer and felt unnecessary.

The Solution:

I’ve added a dedicated Reset Button. It clears the entire proof programmatically in one click, so you don't have to refresh the page or waste time clicking "delete" over and over.

2. Interactive Import Dialogue

The Problem:
The import function was pretty rigid—it only allowed for "prepend" imports (adding data to the very top). If a user wanted to replace their work or just add something to the end, they could not.

The Solution:
I’ve introduced an Import Dialogue Menu. Now, when you bring in a file, you get to choose exactly how it fits into your current project:

• Overwrite: Start fresh with just the imported data.
• Prepend: Add it to the top.
• Append: Tack it onto the end.