Harden Docker container runtime health check

[captainsafia]

Closes #10391.

[Copilot]

Pull Request Overview

This PR strengthens the container runtime health check by verifying that the Docker daemon is running before checking Docker Buildx availability.

• Adds CheckDockerDaemonAsync to probe the Docker daemon via docker container ls -n 1
• Adds CheckDockerBuildxAsync to validate that Buildx is installed and functioning
• Updates CheckIfRunningAsync to chain both checks sequentially

Comments suppressed due to low confidence (1)

src/Aspire.Hosting/Publishing/DockerContainerRuntime.cs:134

• Add unit tests for the new CheckDockerDaemonAsync and CheckDockerBuildxAsync methods, covering both successful and failure paths to ensure the health check logic is fully validated.

    public async Task<bool> CheckIfRunningAsync(CancellationToken cancellationToken)

[Copilot]

[nitpick] Consider using LogWarning or LogError for stderr output to better reflect that this data represents an error stream rather than informational messages.

Suggested change

	logger.LogInformation("docker container ls (stderr): {Error}", error);
	logger.LogWarning("docker container ls (stderr): {Error}", error);

[Copilot]

[nitpick] The OnOutputData and OnErrorData logging closures are duplicated in both health-check methods; consider extracting a shared helper to reduce duplication and improve maintainability.

Suggested change

	OnOutputData = output =>
	{
	logger.LogInformation("docker buildx version (stdout): {Output}", output);
	logger.LogInformation("docker container ls (stdout): {Output}", output);
	},
	OnErrorData = error =>
	{
	logger.LogInformation("docker buildx version (stderr): {Error}", error);
	logger.LogInformation("docker container ls (stderr): {Error}", error);
	},
	OnOutputData = output => LogProcessOutput("stdout", output),
	OnErrorData = error => LogProcessOutput("stderr", error),

[davidfowl]

Do the same for podman?

[captainsafia]

/backport to release/9.4

[github-actions]

Started backporting to release/9.4: https://github.com/dotnet/aspire/actions/runs/16283710455