Add Initial Support for Interval Types (Starting With IntervalNanosecond)

[faridmehrhesam]

Summary

This PR introduces initial support for ClickHouse Interval types, beginning with IntervalNanosecond.
Before implementing the full family of interval types, I’d like to get early feedback to ensure that the approach, structure, and overall direction align with the project’s standards.

What’s Included

• Parsing and serialization support for IntervalNanosecond.
• Initial unit tests covering the new type.

Let me know about the approach, code quality, test coverage, and anything else that should be included before extending support to all interval types — and after the full implementation I will follow the version-update instructions accordingly

Checklist

• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided to include in CHANGELOG

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

❌ Patch coverage is 87.50000% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
ClickHouse.Driver/Types/IntervalType.cs	0.00%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[alex-clickhouse]

Thanks for this!

The docs say the interval should be unsigned, but some quick tests show that is not actually the case, will have to investigate that a bit.

Adding the rest of the interval types would be useful as well, maybe with a common base class and then just multiplying the TimeSpan by some factor?

[faridmehrhesam]

Thanks for the feedback. I’ll continue the implementation and review the docs to stay aligned.