Drop claude-fetcher binary and cron job — the widget's built-in
BackgroundFetcher is the sole fetcher now. Add cmd/setup with cross-platform
install and uninstall (--uninstall): kills widget, removes binaries + autostart,
cleans Claude Code statusline setting, optionally removes config dir.
Also includes: browser-based login (chromedp), ICO wrapper for Windows tray
icon, and reduced icon size (64px).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
