Moves `handleAddProfile` logic from the main application class into `ProfileModalController` to improve separation of concerns as per `AGENTS.md`.
- Extracts `handleAddProfile` to `js/ui/profileModalController.js`.
- Updates `ProfileModalController` to handle add account flow internally.
- Removes legacy callback wiring from `js/app.js` and `js/ui/applicationBootstrap.js`.
- Adds unit tests for the extracted logic in `tests/ui/profileModalController-addProfile.test.mjs`.
Co-authored-by: PR0M3TH3AN <[email protected]>
