fix: search expand animation by using max-width transition

Commit notes

The search expand animation was not working because the CSS transition was set on 'width' property, but the actual sizing used flex-based layout (flex-1 with min/max constraints). CSS cannot interpolate between a fixed width value and a flex-based layout.

Fixed by: - Changed transition-search utility to transition 'max-width' instead of 'width' - Updated LibrarySearchFilter to use explicit max-width values in both states: - Collapsed: max-w-9 (36px) - Expanded: max-w-48 (192px) / max-w-64 (256px) on larger screens

This allows CSS to smoothly animate the max-width property between the collapsed and expanded states.

Co-authored-by: armin.naimi <[email redacted]>