Upgrade Aspire to 13.4.2, refresh all dependencies, and document ATS availability

[Copilot]

Upgrades the Aspire stack to 13.4.2 (required for GA), brings every other dependency to its latest stable version, and corrects the README's now-inaccurate note about Aspire Type System (ATS) attributes.

Aspire 13.4.2

• Bumped Aspire.AppHost.Sdk and all Aspire.* package versions (central + playground/AppHost projects) to 13.4.2.
• Migrated the container-image push path off the removed IResourceContainerImageBuilder. The replacement IResourceContainerImageManager.PushImageAsync(resource, ct) resolves the local image name, computes the registry-qualified remote tag, tags, and pushes internally — collapsing the prior manual tag+push:

var manager = context.Services.GetRequiredService<IResourceContainerImageManager>();
await manager.PushImageAsync(resource, context.CancellationToken);

• Updated verified Aspire manifest snapshots: 13.4.2 no longer emits the $schema line.

Other dependencies

• Test: Microsoft.NET.Test.Sdk 18.6.0, xunit 2.9.3, xunit.runner.visualstudio 3.1.5, coverlet.collector 10.0.1, Verify.Xunit 31.12.5.
• Roslyn: Microsoft.CodeAnalysis.CSharp/.Analyzers 5.3.0. SourceLink 10.0.300. Microsoft.Extensions.* 10.6.0, OpenTelemetry.* 1.15.x.

ATS attributes

• [AspireExport]/[AspireDto]/[AspireExportIgnore] are present in Aspire.Hosting 13.4.2; their validating analyzer is opt-in behind the EnableAspireIntegrationAnalyzers MSBuild flag (default false). README note corrected accordingly.
• Annotating the public surface is deferred: enabling the analyzer raises ASPIREEXPORT008 on every extension method over the Aspire-exported IResourceBuilder<T>, and several domain types (TerraformOutputReference, configuration/block types) must first be made ATS-compatible. Scope flagged for a follow-up.

[Copilot]

Pull request overview

Updates the repository’s Aspire/AppHost integration and overall dependency set to align with Aspire 13.4.2, while adding a cross-language “raw HCL” value-provider escape hatch (TerraformRawExpression) that can flow through Aspire’s expression/value-provider system into the Terraform AST.

Changes:

• Upgraded Aspire (AppHost SDK + Aspire.* packages) to 13.4.2 and refreshed other centrally-managed dependency versions.
• Replaced container image push logic to use IResourceContainerImageManager.PushImageAsync(resource, ct) instead of the removed IResourceContainerImageBuilder.
• Introduced TerraformRawExpression with tests and documentation, and refreshed Verify manifest snapshots to match Aspire 13.4.2 output (no $schema line).

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/EmmittJ.Aspire.Hosting.Terraform.Tests/TerraformRawExpressionTests.cs	Adds unit tests validating raw/unquoted HCL lowering and interaction with ReferenceExpression.
tests/EmmittJ.Aspire.Hosting.Terraform.Tests/TerraformPipelineIntegrationTests.TerraformStack_WithParentConfiguration_UsesParentDirectory/aspire-manifest.verified.json	Updates Verify snapshot to match Aspire 13.4.2 manifest output (drops $schema).
tests/EmmittJ.Aspire.Hosting.Terraform.Tests/TerraformPipelineIntegrationTests.TerraformStack_WithOutputDirectory_GeneratesFileInSpecifiedLocation/aspire-manifest.verified.json	Updates Verify snapshot to match Aspire 13.4.2 manifest output (drops $schema).
tests/EmmittJ.Aspire.Hosting.Terraform.Tests/TerraformPipelineIntegrationTests.TerraformStack_WithComplexConfiguration_GeneratesValidHCL/aspire-manifest.verified.json	Updates Verify snapshot to match Aspire 13.4.2 manifest output (drops $schema).
tests/EmmittJ.Aspire.Hosting.Terraform.Tests/TerraformPipelineIntegrationTests.TerraformStack_GeneratesFileInDefaultLocation/aspire-manifest.verified.json	Updates Verify snapshot to match Aspire 13.4.2 manifest output (drops $schema).
tests/EmmittJ.Aspire.Hosting.Terraform.Tests/TerraformPipelineIntegrationTests.MultipleAnnotations_ContributeToSingleStack/aspire-manifest.verified.json	Updates Verify snapshot to match Aspire 13.4.2 manifest output (drops $schema).
src/EmmittJ.Terraform.Sdk.AppHost/EmmittJ.Terraform.Sdk.AppHost.csproj	Bumps AppHost SDK to Aspire 13.4.2.
src/EmmittJ.Aspire.Hosting.Terraform/TerraformRawExpression.cs	Adds a new Aspire value provider to carry verbatim/unquoted HCL into Terraform expressions.
src/EmmittJ.Aspire.Hosting.Terraform/TerraformPublishingContext.cs	Teaches module-parameter resolution to lower TerraformRawExpression as TerraformExpression.Raw(...).
src/EmmittJ.Aspire.Hosting.Terraform/TerraformProvisioningResource.cs	Migrates container image push to IResourceContainerImageManager and adds support for resolving TerraformRawExpression.
src/EmmittJ.Aspire.Hosting.Terraform/README.md	Documents the cross-language expression contract, raw-HCL escape hatch, and ATS attribute availability/analyzer opt-in.
playground/getting-started/GettingStarted.csproj	Updates Aspire AppHost SDK and Aspire.Hosting.AppHost dependency to 13.4.2.
playground/azure-container-apps/apphost/AppHost.csproj	Updates Aspire AppHost SDK and Aspire.Hosting.* dependencies to 13.4.2.
Directory.Packages.props	Refreshes centrally-managed versions (Aspire, testing, Roslyn, SourceLink, OpenTelemetry, etc.).