UI 1.0

This issue tracks progress towards a finalized UI for the 1.0 release.
Obviously, that means this blocks the 1.0 release.

### Primary design goals
1. Dead simple. The design should never be confusing
2. Transport controls should ALWAYS be visible AND in the same place. No matter what, as long as you're using the app, the pause/play/back/forward/scrubber/etc. should _always_ be right there so you can press them in that moment.
- Acceptable exception: File selection dialogs and other system UI we can't really control
3. Delightful! Users should enjoy using this app. **Frustration is a failure state**
4. Pixel art styling with [Deadass Simple branding](https://github.com/BlueHuskyStudios/Deadass-Simple)

Start by reviewing the current application UI and comparing it with the stated 1.0 design goals. The issue names no files, entry points, or tests, so identify the existing transport controls and other UI surfaces before defining the work. Done means the UI is finalized against the simplicity, persistent-control, delight, and pixel-art branding goals.

Written by the indexing model from the issue text.