Update TagMetadata CSS classes to use brand colours with translucent
backgrounds matching the wireframe design:
- cyan: bg-brand-cyan/10 text-brand-cyan
- pink: bg-brand-pink/10 text-brand-pink
- neutral: bg-zinc-800 text-white (dark: bg-zinc-100 text-black)
Previously used muted Tailwind defaults (bg-cyan-100/text-cyan-900)
which appeared as soft pastels instead of the intended neon look.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>