Added

• Sparkle auto-update. The app now checks brtdv.com/screenshot-shelf for new versions on a schedule and on demand from the menu bar's "Check for Updates…" item.
• Menu bar app that watches the macOS screenshot folder and surfaces new screenshots in a floating, always-on-top shelf.
• Drag thumbnails directly from the shelf into other apps via the standard file pasteboard.
• Auto-dismiss after a configurable interval (10s, 20s, 30s, 1min, 5min, or Never). Hovering the shelf pauses the timers.
• Seven shelf positions: the four corners, the two middle edges, and bottom-center. Corner and edge positions stack vertically; bottom-center stacks horizontally.
• Settings window for the watch folder (auto-detect from `com.apple.screencapture` or a custom path), shelf position, and auto-dismiss interval.