Add optional GDScript linting setup for improved code quality

[Tusharjamdade]

The project currently does not include a standardized linting setup for GDScript, which can result in inconsistent formatting and reduced readability across contributions.

As the codebase grows and more contributors get involved, having a lightweight and optional linting mechanism can significantly improve maintainability.

Problem

• No consistent GDScript style enforcement
• Harder to review PRs due to formatting differences
• Contributors may unknowingly introduce style issues

[Tusharjamdade]

/assign