feat(language): Implement DELETE endpoint for user-specific language deletion

[ricky-ultimate]

Pull Request

Description

This PR introduces a new DELETE API endpoint that allows users to delete a specific language associated with their account. It includes:

New Controller Method: DELETE /languages/:id
Service Method: deleteUserLanguage(languageId, userId)
Validation:

• Ensures the language exists for the requesting user.
• Prevents deletion if dependencies exist.
  Error Handling:
• Returns 404 Not Found if the language does not belong to the user.
• Returns 400 Bad Request if dependencies prevent deletion.
  Unit Tests:
• Added test cases for successful and failed deletions.

Related Issue

Fixes #1074

Type of Change

• feat: New feature
• fix: Bug fix
• docs: Documentation updates
• style: Code style/formatting changes
• refactor: Code refactoring
• perf: Performance improvements
• test: Test additions/updates
• chore: Build process or tooling changes
• ci: CI configuration changes
• other:

How Has This Been Tested?

• Unit tests
• Integration tests
• Manual tests

Test Evidence

Screenshots (if applicable)

Documentation Screenshots (if applicable)

Checklist

• My code follows the project's coding style
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published
• I have included a screenshot showing all tests passing
• I have included documentation screenshots (if applicable)

Additional Notes