fix(visualization): auto-close File Explorer sort dropdown

Migrate the daisyUI sort dropdown from pure-CSS focus-within to a
controlled signal pattern (isOpen + document:click HostListener),
matching MapSelector / DeltaSelector. The menu now closes after the
user picks a sort key, toggles the order, or clicks outside.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>