Fix/Product Category and Variant Relations

[BigLens]

Pull Request

Description

This PR introduces a fix to the Product-Category relationship and ensures proper handling of variants within the Product entity.

Related Issue

#1250

Fixes #1250

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:

## Changes Implemented

• Added Many-to-One and One-to-Many relationships between Product and ProductCategory.
• Updated the Product entity to correctly reference ProductCategory instead of storing it as a string.
• Refactored the seeding script to properly associate products with categories instead of assigning category names as strings.
• Resolved repository injection errors in ProductsService.
• Ensured that all affected code runs without breaking existing functionalities.

How Has This Been Tested?

• Unit tests
• Integration tests
• Manual tests

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

No database migrations were performed, as this is a boilerplate repository.
Migration files may need to be generated and reviewed if this is accepted.