Add NetEvolve.HealthChecks.Npgsql.Devart package for PostgreSQL health checks using Devart provider

[Copilot]

This PR implements a new health check package NetEvolve.HealthChecks.Npgsql.Devart that provides PostgreSQL database health checks using Devart's PostgreSQL provider (Devart.Data.PostgreSql) instead of the standard Npgsql provider.

What's Added

• NetEvolve.HealthChecks.Npgsql.Devart package with complete implementation following established patterns
• Configuration compatibility with existing NetEvolve.HealthChecks.Npgsql package (uses same HealthChecks:PostgreSql configuration section)
• Comprehensive integration tests with proper license requirement handling
• Complete documentation and usage examples

Key Features

The new package provides:

• AddPostgreSqlDevart() extension method for service registration
• Support for both configuration-based and builder-based setup approaches
• Proper timeout handling with degraded status for slow connections
• Validation for connection strings and timeout values
• Default tags: ["postgresql", "database", "devart"]

Usage Examples

Configuration-based approach:

services.AddHealthChecks()
    .AddPostgreSqlDevart("MyDatabase");

Builder-based approach:

services.AddHealthChecks()
    .AddPostgreSqlDevart("MyDatabase", options =>
    {
        options.ConnectionString = "connection string";
        options.Timeout = 5000;
    });

The configuration structure remains compatible with the existing Npgsql package, allowing easy migration:

{
  "HealthChecks": {
    "PostgreSql": {
      "MyDatabase": {
        "ConnectionString": "connection string",
        "Timeout": "5000"
      }
    }
  }
}

Implementation Details

• Uses PgSqlConnection from Devart.Data.PostgreSql package
• Follows the same architectural patterns as NetEvolve.HealthChecks.SqlServer.Devart
• Includes source generator integration for SQL health check implementation
• Comprehensive test coverage with scenarios for healthy, degraded, and unhealthy states
• Tests are marked with license requirement skip (Devart requires commercial license)

Fixes #813.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• www.devart.com
  • Triggering command: curl -s REDACTED (dns block)
• www.nuget.org
  • Triggering command: curl -s REDACTED$filter=Id%20eq%20'Devart.Data.PostgreSql'&$top=1&$select=Description (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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