Merge pull request #72 from h3nock/worktree-dark-mode-polish

Merge branch 'main' into worktree-dark-mode-polish

fix opacity-dimmed text-subtle falling below AA

replace redundant locked badge with coming soon in footer

bump course card tag pills to font-medium

brighten code comment color for AA contrast

update color guide with subtle tier documentation

fix invisible active buttons in rotation matrix interactive

update chapter content labels to text-subtle

update setup and sync pages to use text-subtle

update mdx shared components to use text-subtle

update challenge editor labels and toolbar to text-subtle

update homepage, roadmap, and cards to use text-subtle

update shell chrome from text-muted to text-subtle

add subtle color token to dark and light theme