Electron App: Self-update mechanism

[jongio]

Overview

Auto-update via electron-updater checking GitHub Releases.

Acceptance Criteria

• Check for updates on launch (background, non-blocking)
• Check for updates periodically (every 6 hours while running)
• Update notification badge in UI when new version available
• Update dialog: version, changelog, download progress, install button
• Download update in background
• Install on next restart (or immediately with user confirmation)
• Rollback if update fails
• Update check can be disabled in settings
• Manual 'Check for Updates' in app menu / settings

Implementation

• electron-updater with GitHub Releases as update source
• Differential updates (delta) where possible
• Code signing for macOS (notarization) and Windows (Authenticode)
• Update staging: download → verify signature → stage → restart to apply