Draft: refactor: centralize all enums and validation functionality in app/schemas

Refactoring Request Template

Title (semantic)

Format: refactor(scope): short description Example: refactor(auth): simplify token validation logic

Description

This merge request refactors existing code.

Checklist

• Code has been refactored for clarity, maintainability, or performance.
• No functional changes have been introduced.
• All existing tests are passing.
• Code adheres to project coding standards.

Related Issue(s)

Closes #