Wrap auth-dependent sidebar navigation and meta in ClientOnly with
SSR fallback slots to prevent hydration mismatch that caused all
authenticated nav links to point to wrong pages. Fix admin events
page crash by replacing empty string USelect values with 'all'.
Native <input type="checkbox"> elements were invisible in production
because @tailwindcss/forms is not installed. UCheckbox renders properly
with the Nuxt UI theme.
Standardizes color values and styling using the new tokens:
- Replaces hardcoded colors with semantic variables
- Updates background/text/border classes for light/dark mode
- Migrates inputs to UInput/USelect/UTextarea components
- Removes redundant style declarations
