UI/UX cleanup for the main PremieDrop app

[Lotanami]

PremieDrop works as a beta, but the main interface needs clearer layout and workflow polish.

Areas to look at:

• Make the main file/library flow easier to understand.
• Improve spacing, labels, button grouping, and visual hierarchy.
• Reduce confusion around actions like adding files, importing, downloading, and opening web tools.
• Keep changes focused and easy to review.

Helpful skills:

• UI/UX design
• Desktop app layout
• PyQt experience is useful but not required for design feedback.

Relevant files:

• Main app window and layout: https://github.com/Lotanami/PremieDropRepo/blob/dev-branch/systems/main.py#L3175
• Main controls/button area: https://github.com/Lotanami/PremieDropRepo/blob/dev-branch/systems/main.py#L3424
• Shared UI text, sizes, and theme values: https://github.com/Lotanami/PremieDropRepo/blob/dev-branch/systems/premiedrop_ext/ui_config.py#L7