fix(electron): persist macOS zoom and window bounds across reopen

[passion729]

Summary

Fixes macOS window state persistence issues when reopening the app window without fully quitting.

This PR now covers:

• zoom persistence across close/reopen
• window bounds (size and position) persistence across close/reopen

Fixes #529

Changes

• Persist window zoom factor in app config (windowZoomFactor)
• Apply persisted zoom on window creation and after initial renderer load
• Persist zoom on webContents zoom change events
• Add close-time fallback persistence for zoom on window close
• Capture last-closed window snapshot in WindowManager (workspace, bounds, focused, url)
• On macOS app.activate (Dock reopen with no windows), restore from last-closed/saved window state instead of default window size
• During before-quit, avoid saving an empty window list when all windows were already closed by reusing last-closed window state

Testing

• Manual (macOS):
  1. Open app
  2. Change zoom (Cmd + / Cmd -)
  3. Resize and move window
  4. Close window (Cmd + W / traffic-light close), do not quit app
  5. Reopen from Dock
  6. Verify both zoom and window bounds are preserved
• Verification:
  • bun run typecheck:shared
  • bun run typecheck:electron