FR-22: Automatic system-based dark-mode preference
Description
As a user, I want to be able to use my system's or browser's preferred color mode so that the app matches my system settings.
Acceptance criteria
- AC1 - A user should be able to set their preferred colour mode to be inferred from their system.
- AC2 - If no system colour mode is available, it should default to light mode.
Dependencies
Requires #31 (closed)