Light-dark mode switch not persistent when using back arrow/mouse button

[tmorgan181]

State is static per page. Needs to be cached and checked every time the user navigates, including using the back and forward buttons.

[tmorgan181]

Copilot applied a fix but now the switch flickers when you navigate back after change the theme. Also somehow completely changed the color theme of the light mode lol

TODO: fix light theme colors and switch flicker