Add health checks module

[jongalloway]

Fixes #76

Add health checks module to the application.

• Add Health Check Packages: Add Microsoft.Extensions.Diagnostics.HealthChecks, AspNetCore.HealthChecks.Npgsql, and AspNetCore.HealthChecks.Redis package references to complete/Api/Api.csproj.
• Add Health Check Services: Add health check services for database, redis cache, and external service in complete/Api/Program.cs.
• Add Health Check Endpoints: Add health check endpoints for /health and /alive in complete/Api/Program.cs.
• Considerations for Non-Development Environments: Add considerations for non-development environments in MapDefaultEndpoints method in complete/ServiceDefaults/Extensions.cs.
• Documentation: Add workshop/10-health-checks.md to explain the health checks module and include instructions for students to update the application with health checks. Reference relevant documentation and include information on the HealthChecksUI sample.

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PR Overview

This PR adds a comprehensive health checks module to the application to monitor critical dependencies and expose health endpoints for both development and non-development environments.

• Added documentation for health checks setup.
• Updated Api.csproj and Program.cs to register health check services and endpoints.
• Modified MapDefaultEndpoints in ServiceDefaults/Extensions.cs with distinct logic for non-development environments.

Reviewed Changes

File	Description
workshop/10-health-checks.md	Documentation outlining steps to add health checks to the application
complete/Api/Program.cs	Registers health check services and maps health check endpoints in Program.cs
complete/ServiceDefaults/Extensions.cs	Updates the MapDefaultEndpoints method to handle non-development environments

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (1)

complete/Api/Program.cs:41

• Health check endpoints are being mapped in both MapDefaultEndpoints and again explicitly in Program.cs, which may lead to duplicate route mapping. Consider removing the redundant mapping in Program.cs if MapDefaultEndpoints already handles these endpoints.

app.MapHealthChecks("/health");

[jongalloway]

I am leaning towards closing this PR and potentially revisiting this module in a future release of .NET Aspire.

• .NET Aspire currently creates /health and /alive health check endpoints for all web app projects in Service Defaults. It's possible to add additional health checks via the standard ASP.NET Core Health Checks API, but they're not directly integrated into the .NET Aspire health checks dashboard or dependency management.
• There is a sample to add the HealthChecksUI dashboard via docker image, but this carries other caveats since it shouldn't be run in production without security consideration, and is kind of a side scenario.
• The .NET Aspire docs don't advocate dependency health checks, and there's no direct guidance in the docs or samples.

I had previously discussed with Jeff and he pointed me to this stackoverflow issue describing the above: How to make Health Checks in NET Aspire right way?

I've written and rewritten this several times, and it seems like a poor use of workshop time to cover this currently. There are some open issues to extend health check functionality, at which time it would make sense to create a new PR based on the updated API.

[jongalloway]

Closing the PR per #77 (comment)