feat: add notifications, offline detection, tab duplicate, and settings backup}
- Add desktop notifications system with native OS notification support toggled via Settings; clicking notification brings app to foreground - Add offline detection with auto-reload when connectivity returns, debounced to avoid reload spam on flaky connections - Add tab duplicate via right-click context menu, preserving URL and account type across restarts - Add auto-launch on login option (AppImage/deb/rpm only, hidden on Snap/Flatpak) with minimize-to-tray behavior - Add settings backup/restore to export/import all app settings (tabs, bookmarks, preferences) as a single JSON file - Add auto-translate developer script using Claude CLI to translate missing UI strings from English to all 30 supported locales - Add dynamic Snap Store description generated from README features section during publish via snap-before/snap-after build hooks - Update all 30 translation files with new keys for notifications, offline status, tab duplicate, settings export/import, and login - Update CI workflow to run snap-before/snap-after steps around arm64 snap build - Remove pull_request trigger from test workflow - Bump version to v2026.4.125