fix: correct path derivation in macOS update restart script

[j4rviscmd]

Summary

Fix the macOS auto-update restart failure caused by incorrect path calculation in applyDmgUpdateOnQuit().

Problem

After downloading and extracting the update DMG, clicking "Install & Restart" would:

1. Show "Installing..." (DMG extraction - works correctly)
2. Show "Restarting..." (triggers quit + update script)
3. App closes successfully
4. App never restarts and version remains unchanged

Root Cause

In codermUpdateService.darwin.ts, the applyDmgUpdateOnQuit() method used path.dirname() twice on currentAppPath:

const currentAppPath = electron.app.getAppPath().split('.app')[0] + '.app';
// e.g. currentAppPath = '/Applications/Coderm.app'
const parentDir = path.dirname(path.dirname(currentAppPath));
// path.dirname('/Applications/Coderm.app') → '/Applications'
// path.dirname('/Applications') → '/'  ← BUG: resolves to root!

This caused the update shell script to target /Coderm.app instead of /Applications/Coderm.app, resulting in permission errors and failed restart.

Fix

Remove the extra path.dirname() call:

- const parentDir = path.dirname(path.dirname(currentAppPath));
+ const parentDir = path.dirname(currentAppPath);

Now parentDir correctly resolves to /Applications (or wherever the app is installed), and the update script properly replaces and relaunches the application.