- Side panel widened (~320px) with a resizable divider; loads the original image instead of a 96px thumbnail; click to open full screen. - List ↑/↓ move selection (preview follows); Enter opens full screen. - Full-screen viewer: ←/→ cycle previewable media (wrapping) with a caption. - Lazy windowed rendering: ~20 rows/thumbnails at a time, auto-loading on scroll; list scrolls inside the node (min-height:0 flex fix). - Bump to 0.4.0; update CHANGELOG and README. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>