Fix dotnet watch test stuck after build failures in .NET 10

[Copilot]

In .NET 10, dotnet watch test stops monitoring file changes after a build or compilation error. Users see "Fix the error to continue" but watch ignores subsequent file changes, requiring manual restart.

Root Cause

FileWatcher.WaitForFileChangeAsync() only watched the project file directory non-recursively and only accepted changes to the .csproj file itself. Source file changes went undetected.

Changes

Modified FileWatcher.WaitForFileChangeAsync() to:

• Watch project directory tree recursively (includeSubdirectories: true)
• Accept any file change except:
  • bin/ and obj/ directories (build artifacts)
  • Hidden directories (.git, .vs, etc.)
• Log actual changed file path instead of project file path

Before:

watcher.WatchContainingDirectories([filePath], includeSubdirectories: false);
var fileChange = await watcher.WaitForFileChangeAsync(
    acceptChange: change => change.Path == filePath,
    startedWatching,
    cancellationToken);

After:

watcher.WatchContainingDirectories([filePath], includeSubdirectories: true);
var fileChange = await watcher.WaitForFileChangeAsync(
    acceptChange: change =>
    {
        var relativePath = projectDir != null 
            ? Path.GetRelativePath(projectDir, change.Path)
            : change.Path;
        var pathParts = relativePath.Split(new[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }, StringSplitOptions.RemoveEmptyEntries);
        
        return pathParts.Length == 0 || 
               (!pathParts[0].Equals("bin", StringComparison.OrdinalIgnoreCase) &&
                !pathParts[0].Equals("obj", StringComparison.OrdinalIgnoreCase) &&
                !pathParts[0].StartsWith(".", StringComparison.Ordinal));
    },
    startedWatching,
    cancellationToken);

Applies to both dotnet watch test (non-hot-reload) and dotnet watch run (hot-reload) code paths.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Continuous testing broken on net10 (dotnet watch test)</issue_title>
<issue_description>### Describe the bug
The command "dotnet watch test" does not work as expected in .net 10. When a test fails or does not compile the command stops monitoring the changes and even though you fix the issue it does not rerun the tests and get stuck with the message "Fix the error to continue or press Ctrl+C to exit.".

To Reproduce

There are two repositories with 12 steps each one, one for the .net9 that works and one for .net10 that does not work:
https://github.com/xcap2000/continuous-testing-net9
https://github.com/xcap2000/continuous-testing-net10

Exceptions (if any)

No exceptions displayed.

Further technical details

I am running in the command line just to isolate the issue, usually I run through tasks in vscode.
The dotnet info will vary if you run the .net 9 or .net 10 because of the global.json defined in each of the projects.
You should be able to run both projects if you have any version of .net9 and any version of .net10 to reproduce the issue.</issue_description>

Comments on the Issue (you are @copilot in this section)

@Youssef1313 @tmat Looks like a regression here.

• Fixes Continuous testing broken on net10 (dotnet watch test) #52528

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