Uses Tailwind v4 class-based dark mode with a Stimulus controller for
toggling. Respects prefers-color-scheme as default, prevents FOUC with
an inline script, and persists the user's choice in localStorage. All
views updated with dark: variants for backgrounds, text, borders,
badges, buttons, and form inputs.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
