Properly typedef code for improved maintainability and clarity

[jaspermayone]

Description

The current codebase lacks consistent and comprehensive use of TypeScript type definitions. This makes it harder to understand data structures, increases the risk of runtime errors, and complicates onboarding for new contributors.

Goals

• Introduce or improve TypeScript typedefs across the codebase.
• Ensure all major interfaces, function signatures, and data models are explicitly typed.
• Improve developer experience and reduce potential bugs by leveraging TypeScript's static typing.

Tasks

• Audit the codebase to identify areas lacking proper type definitions.
• Define and document common interfaces and types in a centralized location (e.g., types/ directory).
• Refactor existing code to use the new or improved types.
• Add type-checking to CI if not already present.

Additional Context

This issue is linked to PR #83, which began restructuring the code. However, further work is needed to ensure type safety is fully implemented across the project.