Add ASP.NET Core one-shot compilation status mode for AI/automation workflows

[Copilot]

The diagnostics compilation page is human-centric and awkward for agent workflows that need a single machine-readable result and process termination. This change introduces an ASP.NET Core one-shot mode triggered by DOTVVM_COMPILATION_STATUS=1 that initializes DotVVM, compiles all views, emits compilation status payload, and stops the app.

• Shared compilation-status response contract

  • Added DotvvmCompilationStatusApi to centralize status generation used by both HTTP API and one-shot mode.
  • Returns:
    • 200 with no body when all files compile
    • 500 with JSON array of failed files when compilation fails

• Reuse in existing diagnostics API presenter

  • CompilationPageApiPresenter now delegates to the shared helper to keep API and one-shot output semantics aligned.

• ASP.NET Core one-shot execution path

  • In UseDotVVM, when DOTVVM_COMPILATION_STATUS=1:
    • DotVVM startup/configuration runs normally
    • compilation status is computed once
    • stdout prints status code (and JSON error payload on failure)
    • process exit code is set (0 for success, 1 for failure)
    • host shutdown is requested via IHostApplicationLifetime

• Focused unit coverage for status mapping

  • Added tests for the shared helper to validate CompileAll result → (status code, body) mapping.

var status = await DotvvmCompilationStatusApi.GetStatusResponse(compilationService);

Console.WriteLine(status.StatusCode);
if (status.ResponseBody is {} body)
{
    Console.WriteLine(body);
}
Environment.ExitCode = status.StatusCode == 200 ? 0 : 1;

[tomasherceg]

@copilot Add an end-to-end test that when we run the samples.aspnetcore app with the env variable, the desired output is actually written on the stdout.

[Copilot]

@copilot Add an end-to-end test that when we run the samples.aspnetcore app with the env variable, the desired output is actually written on the stdout.

Implemented in ecb0b30. I added an end-to-end MSTest (CompilationStatusMode_AspNetCoreSample_WritesStatusToStdout) that builds and runs src/Samples/AspNetCore/DotVVM.Samples.BasicSamples.AspNetCore.csproj with DOTVVM_COMPILATION_STATUS=1, then verifies the status code is printed to stdout, exit code mapping is correct, and the 500-case payload is valid JSON.