Migrate Windows build pools from VS2026 preview scout to production VS2026 image

[Copilot]

Switches all Windows agent pool image references from the VS2026 Preview Scout image to the stable production VS2026 image.

Description

• windows.vs2026preview.scout.amd64 → windows.vs2026.amd64
• windows.vs2026preview.scout.amd64.open → windows.vs2026.amd64.open

Files updated:

• eng/pipelines/common/xplat-setup.yml — official and public Windows build pools
• eng/pipelines/libraries/fuzzing/deploy-to-onefuzz.yml — fuzzing job pool
• eng/pipelines/libraries/stress/ssl.yml — SSL stress test pool
• eng/pipelines/libraries/stress/http.yml — HTTP stress test pool

Original prompt

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This section details on the original issue you should resolve

<issue_title>Migrate from VS2026 Preview Scout to production VS2026 build image</issue_title>
<issue_description>We currently use the VS2026 preview scout image (windows.vs2026preview.scout.amd64) across our Windows build pools. Once the production VS2026 image becomes available, we should migrate to it for stability and long-term support.

Likely files to update:

eng/pipelines/common/xplat-setup.yml - Official and public Windows build pools
eng/pipelines/libraries/fuzzing/deploy-to-onefuzz.yml - Fuzzing job pool
eng/pipelines/libraries/stress/ssl.yml - SSL stress test pool
eng/pipelines/libraries/stress/http.yml - HTTP stress test pool

Expected changes:

windows.vs2026preview.scout.amd64 → windows.vs2026.amd64
windows.vs2026preview.scout.amd64.open → windows.vs2026.amd64.open</issue_description>

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

@steveisok https://github.com/dotnet/dotnet/issues/4320 is the VMR counterpart.

• FixesMigrate from VS2026 Preview Scout to production VS2026 build image #123561

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[Copilot]

Pull request overview

This PR migrates Windows build agent pools from the Visual Studio 2026 Preview Scout image to the stable production VS2026 image across the runtime repository's pipeline configuration files. The migration standardizes the build infrastructure by removing preview/scout image references and adopting the production-ready image names that follow the established naming convention for internal (windows.vs2026.amd64) and public (windows.vs2026.amd64.open) build pools.

Changes:

• Updated image references from windows.vs2026preview.scout.amd64[.open] to windows.vs2026.amd64[.open]
• Applied consistently across official builds, public builds, and stress/fuzzing test pipelines
• Affects all Windows-based pipeline jobs in the runtime repository

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
eng/pipelines/common/xplat-setup.yml	Updated both official (internal) and public Windows build pool image references to production VS2026
eng/pipelines/libraries/fuzzing/deploy-to-onefuzz.yml	Migrated OneFuzz fuzzing deployment job to production VS2026 internal image
eng/pipelines/libraries/stress/ssl.yml	Updated SSL stress test Windows job to production VS2026 public image
eng/pipelines/libraries/stress/http.yml	Updated HTTP stress test Windows job to production VS2026 public image

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[akoeplinger]

@steveisok