# Track Specification: GUI Decoupling & Controller Architecture

## Overview
`gui_2.py` is a monolithic God Object. This track extracts its business logic and state machine into `app_controller.py`, leaving the GUI as a pure immediate-mode view adhering to Data-Oriented Design.

## Functional Requirements
- Create `app_controller.py`.
- Migrate state variables and lifecycle methods from `gui_2.py` to the controller.
- Ensure `gui_2.py` only reads state and dispatches events.