Lumen 0.3.6

Sidebar folder tree, Finder-style

• Clicking a folder always selects it AND toggles its children. Clicking an expanded folder while browsing another album now folds it immediately — no second click, no swallowed clicks (input was rewritten at the AppKit event level; SwiftUI row gestures were dropping ~3 of 4 clicks on the List).
• Keyboard navigation is calm now. ↑/↓ only move the selection — folders no longer unfold as you arrow past them; → reveals the selected folder's children, ← folds them.

Fixes

• Favorite/label counting sent a per-photo round-trip to the NAS — large favorite sets could freeze the main thread.
• Thumbnails and badges went blurry after moving the window to a display with a different scale.
• A batch of async-pipeline hardening from an internal review: list-view selection could reference phantom photos after navigating to a smaller scope; a library reconcile finishing during rapid edits could revert them; a corrupted cache file could crash-loop the launch; a failed cache write could drop the cached library; fast typing in search could spawn duplicate full-library sorts.