Add WithGoModTidy and WithGoModDownload for Golang integration

[Copilot]

Adds support for running go mod tidy or go mod download before a Golang application starts, following the pattern established by Bun/Deno integrations.

Changes

• GoModInstallerResource: New resource type extending ExecutableResource for the Go module installer
• WithGoModTidy(): Runs go mod tidy to clean up and verify dependencies before app start
• WithGoModDownload(): Runs go mod download to download dependencies before app start
• Both methods only execute in development mode, create a parent-child relationship in the dashboard, and support optional installer configuration

Usage

var golang = builder.AddGolangApp("golang", "../gin-api")
    .WithGoModTidy()
    .WithHttpEndpoint(env: "PORT");

// Or with customization
var golang = builder.AddGolangApp("golang", "../gin-api")
    .WithGoModDownload(installer => 
        installer.WithEnvironment("GOPROXY", "https://proxy.golang.org,direct"))
    .WithHttpEndpoint(env: "PORT");

Based on the approach suggested in davidfowl/aspire-13-samples.

Original prompt

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This section details on the original issue you should resolve

<issue_title>go mod tidy/go download</issue_title>
<issue_description>### Related to an existing integration?

Yes

Existing integration

Golang

Overview

We could add go mod tidy/go downlaod to our golang integration. @davidfowl suggested a possible implementation here: https://github.com/davidfowl/aspire-13-samples/blob/731a43a848706cf0bbcece1506122e5b6c19f2d8/golang-api/apphost.cs#L53-L61

Usage example

The api is internal to the golang resource.

Breaking change?

No

Alternatives

Manually run by user.

Additional context

No response

Help us help you

Yes, I'd like to be assigned to work on this item</issue_description>

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

Custom agent used: Hosting Integration Creator
This agent helps users create new hosting integration in Aspire by scaffolding the correct projects and files based on user input.

• Fixes go mod tidy/go download #975

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[davidfowl]

We use the same installer resource and swap out the command. See npm and python. We've also made some changes to how it works with respect to what install: true means

[tommasodotNET]

We use the same installer resource and swap out the command. See npm and python. We've also made some changes to how it works with respect to what install: true means

do you mean these classes?
https://github.com/dotnet/aspire/blob/main/src/Aspire.Hosting.JavaScript/JavaScriptPackageInstallerAnnotation.cs
https://github.com/dotnet/aspire/blob/main/src/Aspire.Hosting.JavaScript/JavaScriptPackageManagerAnnotation.cs
https://github.com/dotnet/aspire/blob/main/src/Aspire.Hosting.JavaScript/JavaScriptInstallerResource.cs

[aaronpowell]

oh wait, IIRC there was a new installer base stack coming wasn't there @davidfowl ?