Cut over dotnetup bootstrap to versioned signed daily aka.ms link

[nagilson]

Part 3 of migrating dotnetup bootstrap scripts to versioned, signed daily aka.ms links. Tracks #54990.

The get-dotnetup.{ps1,sh} scripts are now published as signed Arcade blob artifacts and served via the version-stable link https://aka.ms/dotnet/dotnetup/daily/get-dotnetup.{ps1,sh}. This repoints eng/dotnetup-shared.{ps1,sh} off the legacy raw-GitHub vanity link (aka.ms/dotnetup/get-dotnetup.*) to the signed daily link.

Verified the daily link is live before cutover

• aka.ms/dotnet/dotnetup/daily/get-dotnetup.{ps1,sh} (and .sha512) resolve to the published blob (ci.dot.net/public/dotnetup/0.1.4-preview.6.26356.1/...), not raw GitHub.
• get-dotnetup.ps1 Authenticode signature reports Valid (CN=.NET, O=Microsoft Corporation).
• Served .sha512 matches the served script bytes.

Notes

• On main there is no local scripts/get-dotnetup.*, so the aka.ms URL path is actually exercised here.
• The documentation/general/dotnetup/README.md snippets and the legacy vanity-link retirement live on release/dnup and are handled separately.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

[Copilot]

Pull request overview

Updates the dotnetup bootstrap “shared” install helpers to download the installer script from the new version-stable, signed daily aka.ms link, replacing the legacy vanity link. This keeps eng/dotnetup-shared.{ps1,sh} aligned with the ongoing dotnetup bootstrap migration (tracked by #54990).

Changes:

• Repoint the bash bootstrap helper to https://aka.ms/dotnet/dotnetup/daily/get-dotnetup.sh.
• Repoint the PowerShell bootstrap helper to https://aka.ms/dotnet/dotnetup/daily/get-dotnetup.ps1.
• Update the inline documentation comments in both scripts to match the new source URL.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
eng/dotnetup-shared.sh	Switches the download URL and updates the corresponding comment to the signed daily aka.ms endpoint.
eng/dotnetup-shared.ps1	Switches the download URL and updates the corresponding comment to the signed daily aka.ms endpoint.

[dsplaisted]

@nagilson I think maybe we should stick with the shorter redirects (for example https://aka.ms/dotnetup/get-dotnetup.sh) as the entry point. We can edit those redirects to redirect to the daily channel (and eventually the preview or stable channel).

It doesn't matter so much for scripts, but I think it's best to use shorter links for our getting started instructions, and probably the scripts should be consistent with that.

@baronfel Any thoughts?

[nagilson]

Definitely in favor of pointing users to the shorter vanity one though for CI I think we should stick to the specific versioned ones, so we can test changes to the script and use daily scripts on release/dotnetup but use stable / preview scripts in the sdk and elsewhere at the same time once we have that.

[nagilson]

Updated #55154 based on your feedback.