feat(examples): add ASP.NET health checks example

[alex-clickhouse]

Note

Adds an ASP.NET health checks example and wires it into the examples app.

• New AspNet_001_HealthChecks.cs: implements ClickHouseHealthCheck (runs SELECT 1), DI-based registration, and AddClickHouse IHealthChecksBuilder extension; demo Run() uses AddClickHouseDataSource and HealthCheckService
• Program.cs: invokes AspNetHealthChecks.Run() under NET7_0_OR_GREATER
• ClickHouse.Driver.Examples.csproj: adds Microsoft.Extensions.Diagnostics.HealthChecks package
• README.md: new "ASP.NET Integration" section linking the health checks example

^{Written by Cursor Bugbot for commit 1cd7695. This will update automatically on new commits. Configure here.}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!