AmbientMetadata.Build - release to GA

[evgenyfedorov2]

Microsoft Reviewers: Open in CodeFlow

Link to the respective API review: #6628
Link to the previous PR: #6628

[Copilot]

Pull request overview

This PR transitions the Microsoft.Extensions.AmbientMetadata.Build library from development stage to General Availability (GA). The library provides runtime information for build-related ambient metadata including build ID, build number, source branch name, and source version. This release marks the library as production-ready with stable APIs.

Key changes:

• Removed experimental attribute markers (InjectExperimentalAttributeOnLegacy and StageDevDiagnosticId) from the project configuration
• Updated stage from dev to normal to indicate GA readiness
• Added API baseline manifest marking all public APIs as "Stable"

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
Microsoft.Extensions.AmbientMetadata.Build.csproj	Removes experimental markers, updates stage to 'normal', and adds EnablePackageValidation>false
Microsoft.Extensions.AmbientMetadata.Build.json	Adds new API baseline manifest declaring all public APIs (BuildMetadata class and BuildMetadataServiceCollectionExtensions) as stable with version 10.2.0.0

[amadeuszl]

It was added in Nov so in v10, we will have it for 2 months in experimental, as it's small and haven't seen any issues reported - it's fine for me.