feat: Implement TypeInfoKind::Error for type poisoning

[CMI-James]

Description

Closes #72

Changes proposed

What were you told to do?

I was tasked with implementing Error Type Poisoning to prevent cascading errors in the type checker. This involved adding a TypeInfoKind::Error variant similar to rustc's TyKind::Error and updating the type checker to gracefully handle these error types.

What did I do?

Implemented TypeInfoKind::Error

• Added Error variant to the TypeInfoKind enum in core/type-checker/src/type_info.rs.
• Updated Display implementation to show {unknown} for error types.
• Added is_error() helper method to TypeInfo.
• Updated substitute and has_unresolved_params to handle Error variants neutrally.

Updated Type Checker Logic

• Modified core/type-checker/src/type_checker.rs to use TypeInfoKind::Error for type poisoning.
• Updated infer_expression for Identifier, Struct initialization, MemberAccess, TypeMemberAccess, and FunctionCall to return TypeInfoKind::Error upon lookup failure instead of None or continuing with invalid types.
• Updated type mismatch checks in Statement::Assign, Statement::Return, Statement::If, Statement::Loop, and others to suppress errors if either the expected or found type is Error.
• Updated Expression::ArrayIndexAccess, Expression::PrefixUnary, and Expression::Binary to propagate Error types and suppress secondary errors (e.g., "expected array type" when the array expression itself failed).

Benefits

• Prevents cascading errors when a type lookup fails.
• Allows type checking to continue more gracefully.
• Aligns with rustc's error handling model.

Check List (Check all the applicable boxes)

🚨Please review the contribution guideline for this repository.

• My code follows the code style of this project.
• This PR does not contain plagiarized content.
• The title and description of the PR is clear and explains the approach.
• I am making a pull request against the dev branch (left side).
• My commit messages styles matches our requested structure.
• My code additions will fail neither code linting checks nor unit test.
• I am only making changes to files I was requested to.

Screenshots/Videos

[SurfingBowser]

Please confirm you have read this contributor guide and followed the instructions. @CMI-James

[CMI-James]

@SurfingBowser new PR #107 following contributors guide.