This PR completes the migration from traditional ASP.NET Core controllers to modern Minimal APIs, implementing .NET 9 best practices throughout the NLWebNet library.

Changes Made

🔄 Minimal API Migration

• Converted all endpoints to use TypedResults instead of Results for improved type safety
• Added strongly typed return signatures for better compile-time checking
• Implemented .NET 9 best practices for parameter binding and dependency injection

🗑️ Legacy Code Removal

• Removed AskController.cs and McpController.cs - controllers completely eliminated
• Deleted Controllers directory - no longer needed
• Removed controller registrations from ServiceCollectionExtensions.cs
• Eliminated legacy MapNLWebNetControllers() method from extension methods

🧪 Test Updates

• Removed controller test files (AskControllerTests.cs, McpControllerTests.cs)
• Maintained endpoint test coverage - all functionality preserved (35/35 tests passing)
• Reduced test count from 50 to 35 due to controller test removal

📚 Documentation Updates

• Updated development guide to reflect Minimal APIs exclusively
• Removed controller references from API documentation
• Updated project structure diagrams and examples
• Modernized code samples to use service patterns instead of controllers

Benefits

• Better Type Safety: TypedResults provide compile-time type checking
• Improved Performance: Minimal APIs have lower overhead than controllers
• Modern .NET 9 Patterns: Full adoption of current best practices
• Cleaner Architecture: Simplified dependency injection and routing
• Reduced Complexity: Eliminated dual controller/endpoint maintenance

Before/After Comparison

Before (Controllers)

[ApiController]
[Route("ask")]
public class AskController : ControllerBase
{
    public async Task<IActionResult> ProcessQuery([FromBody] NLWebRequest request)
    {
        var response = await _nlWebService.ProcessRequestAsync(request);
        return Ok(response);
    }
}

After (Minimal APIs with TypedResults)

private static async Task<Results<Ok<NLWebResponse>, BadRequest<ProblemDetails>, StatusCodeHttpResult>> ProcessQueryAsync(
    [FromBody] NLWebRequest request,
    INLWebService nlWebService, ILoggerFactory loggerFactory,
    CancellationToken cancellationToken = default)
{
    var response = await nlWebService.ProcessRequestAsync(request, cancellationToken);
    return TypedResults.Ok(response);
}

Testing

• ✅ All builds successful (Debug/Release)
• ✅ All tests passing (35/35)
• ✅ Endpoint functionality preserved
• ✅ API contract unchanged for consumers

Fixes #26.

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