Add automatic update notifications on app startup

[AIEraDev]

Summary

This PR adds a beautiful auto-update notification system that checks for new releases on app startup and prompts users to update with a single click.

Features

🎯 Automatic Update Checks

• Checks for updates 3 seconds after app startup (non-blocking)
• Uses existing infrastructure
• Queries GitHub releases endpoint for latest version
• Silent when already on latest version

🎨 Beautiful Update Banner

• Glassmorphic floating pill that slides up from the bottom of the screen
• Shows current version and new available version
• Live download progress bar with real-time percentage during installation
• Update button: Downloads and installs update, then auto-relaunches app
• Dismiss button (✕): Hides banner and remembers choice for current session
• Elegant fade and slide animations

🧠 Smart Session Management

• Dismissed updates are stored in sessionStorage
• Same version won't re-appear within the same app session
• Will check again on next app launch
• Doesn't spam users with repeated notifications

Implementation

New Files

1. src/hooks/useAutoUpdater.ts

   • React hook that manages update checking lifecycle
   • Tracks update state (idle, checking, available, downloading, installing)
   • Returns update version, download progress, and action handlers
   • Handles sessionStorage for dismissed updates

2. src/components/ui/UpdateBanner.tsx

   • Beautiful floating notification banner component
   • Positioned as fixed overlay (doesn't interfere with app UI)
   • Real-time progress bar during download
   • Smooth animations and transitions

3. src/App.tsx (modified)

   • Integrates useAutoUpdater hook on app mount
   • Renders UpdateBanner as portal-level component
   • Positioned outside modals for maximum visibility

User Experience

Flow

1. User launches Clypra
2. After 3 seconds, app silently checks for updates
3. If new version available → banner slides up from bottom
4. User clicks "Update" → download starts with progress bar
5. Download completes → app automatically relaunches with new version
6. Or user clicks ✕ → banner hides, won't show again this session

No Impact on Current Features

• Settings > About still has manual "Check for Updates" button
• Manual check shows full UI with changelog
• Auto-update is non-intrusive and dismissible
• App remains fully functional during all update operations

Infrastructure

All infrastructure was already in place:

• ✅ tauri-plugin-updater in Cargo.toml
• ✅ Updater endpoint in tauri.conf.json
• ✅ updaterService.ts frontend service
• ✅ Capabilities configured
• ✅ Release workflow generates updater artifacts

This PR only adds the missing automatic check + notification UI.

Testing

• ✅ TypeScript compilation: 0 errors
• ✅ Component renders without crashing
• ✅ Update detection works with version comparison
• ✅ Session storage persists dismissed versions
• ✅ Progress bar updates during download

Benefits

• 📱 Users stay up-to-date automatically
• 🎨 Beautiful, non-intrusive UI
• ⚡ Fast and responsive (3s delay, non-blocking)
• 🧠 Smart enough not to spam users
• 🔄 Seamless update experience with auto-relaunch

Next Steps

After merging:

1. Users on v1.0.5 will get this auto-update feature
2. Future releases will automatically notify users
3. No manual update checks needed for most users