Replace obsolete IWebHost and WebHost APIs with modern Host pattern

[Copilot]

Fixes the build errors caused by obsolete ASP.NET Core hosting APIs by replacing them with the modern hosting pattern.

Original issue description:

Error: /home/runner/work/Pomelo.EntityFrameworkCore.MySql/Pomelo.EntityFrameworkCore.MySql/test/EFCore.MySql.IntegrationTests/Program.cs(44,23): error ASPDEPR008: 'IWebHost' is obsolete: 'IWebHost is obsolete. Use IHost instead. For more information, visit https://aka.ms/aspnet/deprecate/008.' [/home/runner/work/Pomelo.EntityFrameworkCore.MySql/Pomelo.EntityFrameworkCore.MySql/test/EFCore.MySql.IntegrationTests/EFCore.MySql.IntegrationTests.csproj]
Error: /home/runner/work/Pomelo.EntityFrameworkCore.MySql/Pomelo.EntityFrameworkCore.MySql/test/EFCore.MySql.IntegrationTests/Program.cs(46,20): error ASPDEPR008: 'WebHost' is obsolete: 'WebHost is obsolete. Use HostBuilder or WebApplicationBuilder instead. For more information, visit https://aka.ms/aspnet/deprecate/008.' [/home/runner/work/Pomelo.EntityFrameworkCore.MySql/Pomelo.EntityFrameworkCore.MySql/test/EFCore.MySql.IntegrationTests/EFCore.MySql.IntegrationTests.csproj]

Changes Made

• Return Type: Changed BuildWebHost method return type from IWebHost to IHost
• Host Builder: Replaced WebHost.CreateDefaultBuilder(args) with Host.CreateDefaultBuilder(args).ConfigureWebHostDefaults()
• Using Statements: Updated imports to use Microsoft.Extensions.Hosting instead of obsolete Microsoft.AspNetCore
• SDK Version: Updated to use .NET 10.0.100-preview.7.25380.108 as requested

The changes maintain the same functionality while using the modern ASP.NET Core hosting pattern that is compatible with .NET 10.

Fixes #88.

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[renemadsen]

@copilot instructions have been updated to use dotnet 10.0.100-preview.7.25380.108

[Copilot]

@copilot instructions have been updated to use dotnet 10.0.100-preview.7.25380.108

Updated to use .NET 10.0.100-preview.7.25380.108 SDK and successfully fixed the obsolete IWebHost/WebHost API issues. The code now uses the modern Host.CreateDefaultBuilder().ConfigureWebHostDefaults() pattern instead of the deprecated WebHost APIs. Changes committed in a2d521f.