Make model selector dropdown responsive:
- Mobile: full width (w-full max-w-[100vw])
- Desktop: adapts to longest model name (sm:w-max)
- Replace TruncatedText with responsive span (truncate on mobile, full text on desktop via sm:overflow-visible sm:whitespace-nowrap)
- Center status icons in fixed 24px wrapper to prevent layout shifts
- Add sm:pr-2 padding between text and icon zone on desktop
Fixes dropdown cutting off long model names on desktop while maintaining full-width display on mobile with proper text truncation