feat: add fluentValidation validators for the min-max values

[mihailkitrozoskicodechem]

What Changed?

Added FluentValidation rules to enforce valid min–max value constraints and prevent invalid configurations at the API level.

Added xUnit tests for the DomainModelEditor.

Why?

To prevent invalid data - minimum and maximum values from being submitted to the API.
Closes

Type of Change

• 🐛 Bug fix (fixes an issue without breaking existing functionality)
• ✨ New feature (adds new functionality without breaking existing features)
• 💥 Breaking change (existing functionality will be affected)
• 📝 Documentation update
• 🔧 Maintenance (refactoring, dependencies, configuration)

How Did You Test This?

What I tested:

How to test it:

Review Checklist

• My code follows the project's style and conventions
• I've reviewed my own code for obvious issues
• [] I've added comments where the code might be confusing
• [] I've updated relevant documentation (if needed)
• I've tested my changes and they work as expected

Screenshots / Additional Context

[mihailkitrozoskicodechem]

TODO: Create tests for the fluentValidation Validators for the Min-Max values