`Player.gd`

8-directional movement + attack. Introduced Ch. 3, extended in Ch. 5. - **`GameManager.gd`** — autoload, progression state, `has_item` / `add_item`. Introduced Ch. 6, extended Ch. 7. - **`BoundarySystem.gd`** / **`DoorLock.gd`** — rule enforcement, gating. Introduced Ch. 7. - **`ScreenShake.gd`** /