refactor(AnimatedDropdown): convert to native select element

Commit notes

- Replace Melt UI Popover-based dropdown with native <select> - Simplify API to accept options array and value props - Update LibraryFilters.svelte to use new native select API - Update SharePopover.svelte to use new native select API - Style native select to match dark theme with custom caret icon

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