Define Integer Type in AST (Abstract Syntax Tree)

[kh3rld]

Implement the structure of the int type within the Abstract Syntax Tree (AST) to ensure that integer literals are recognized and properly parsed.

Tasks:

• Add an IntNode in the AST to represent integer literals.
• Update the parser to identify integer tokens and generate IntNode instances.
• Write unit tests to validate that integer literals are correctly parsed and represented in the AST.

Acceptance Criteria:

• AST correctly represents integer literals.
• Unit tests cover both positive and negative integer values.