test: parameterize repetitive type validation tests

[durdana3105]

Description

Refactors repetitive type validation tests to use Vitest's it.each() for cleaner and more maintainable test coverage.

Changes

• Parameterized ModelTier validation tests using it.each()
• Replaced repetitive ProviderHealth tests with table-driven test cases
• Grouped related scenarios into reusable datasets
• Reduced duplicated assertion logic
• Preserved the existing type validation behavior and coverage

Testing

• Ran the type validation test suite successfully
• Ran the complete Vitest suite to verify no regressions

Closes #64