[Refactor] Extract LEVEL_DATA constants from OverclockGame.tsx

[bayyubenjamin]

Description
Currently, the LEVEL_DATA array (containing multipliers, risk levels, and color styles) is hardcoded inside app/components/OverclockGame.tsx. This makes it hard to manage game configuration.

Task

1. Create a new file app/lib/gameConfig.ts.
2. Move the LEVEL_DATA constant array to that file and export it.
3. Import LEVEL_DATA back into OverclockGame.tsx.

Why?
Separating configuration from UI logic improves code maintainability.

Labels: refactor, good first issue, clean-code