Replace wait-on with native bundle readiness polling

- remove `wait-on` usage in `dev-electron.mjs`
- add `fs.existsSync` polling for desktop/server bundle files with timeout error details
- keep startup flow the same while reducing external dependency
0bca5a4215Julius Marminge committed on 2/18/2026, 3:49:54 AMparenta293a01
1 file changedLine totals unavailable