UI and Branding Overhaul

The current UI is sophomoric and should be redesigned to better suit the image of a serious piece of editing software.

[ ] Replace current handcrafted HTML UI with something more professional
- maybe flutter?
[ ] Implement a windowing system for computer users so that both draw and proof mode can be seen at the same time.
- Probably golden-layout works very well on godbolt
[ ] rebrand from Peirce-My-Heart to the acronym PMH to keep the original vibe but come off as a more serious software.

RAIRLab / Peirce-My-Heart