[JoeRobich]

Adds publishing scripts and pipeline to publish dnup preview builds to the CDN.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
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[Copilot]

🟡 Changes recommended

Both ESRP contact lists use commas instead of the required semicolons and are passed unchanged to the ReleaseStudio template, leaving a critical configuration issue.

1 open issue

• Use semicolon-separated ESRP contact lists · New

What changed in this PR

Adds a manually triggered pipeline to publish signed dnup preview builds to the CDN through ESRP, without rebuilding assets or changing existing download aliases.

Changes:

• Validates the selected BAR build and stages signed assets for publishing.
• Verifies source checksums, signatures, and CDN downloads, with offline validation fixtures.
• Documents pipeline setup, release inspection, and constraints on switching aliases.

File	Description
eng/​pipelines/​dotnetup-release.yml	Adds release preparation, ESRP publishing, and metadata retention.
eng/​pipelines/​dotnetup-publishing.tests.ps1	Adds offline fixtures for build, asset, and CDN validation.
eng/​pipelines/​dotnetup-publishing.ps1	Implements release eligibility, staging, and download verification.
documentation/​general/​dotnetup/​releasing.md	Documents setup, release operation, and alias-transition precautions.

_{Review effort: Balanced}