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)

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Screenshots/Videos

[SurfingBowser]

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