fix(ci): safely restore v2 Hidi Docker dependencies from approved feed

[Gavin Barron (gavinbarron)]

Summary

Port only the safe Docker feed restore behavior from microsoft/OpenAPI.NET#3107 and the destination main follow-up #890 to support/v2, based on merged #883/#888 at ba2f31f47d9fb84b30df2f67cbe98c5d26fc69f5.

• Add an optional BuildKit nuget_config secret mount to the existing Docker publish command. Local and GitHub Actions builds without a secret retain default NuGet sources and public signing.
• Authenticate the single protected stable container job to the approved GraphDeveloperExperiences_Public feed. Write the XML-escaped job token only into a unique agent-temp config outside the build context/artifacts, restrict permissions to 0600 before writing credentials, pass it through --secret, clear the inherited token environment, and remove the file in finally.
• Fail explicitly on missing token or failed ACR login, platform setup, BuildX creation, or Docker build/push. Document feed/environment owner authorization requirements.

Exactly three files change. Preserve Hidi 2.12.2/2.x, .NET 8, dependencies, public signing identities, HidiDockerContext artifact shape and explicit Dockerfile/context inputs, ACR service connection, docker-images-deploy approvals, stable own-version + latest tags, linux/amd64 + linux/arm64/v8, and existing ESRP/1ES NuGet publishing contracts. No main-only features or preview publishers are imported.

Validation

• YAML parse and PowerShell AST parse passed. Normalized pipeline is identical to the v2 base outside the added container authentication and AzureCLI credential script; version/dependency/framework/signing/publisher contracts are unchanged.
• Parent-owned mock harness: all six scenarios passed (success, missing token, ACR login failure, platform setup failure, BuildX creation failure, build failure), covering approved-feed-only XML escaping, empty file with owner-only permissions before credential write, unique agent-temp path, inherited-token clearing, explicit context/identity, and cleanup. No native Azure or Docker commands were invoked by that harness.
• Staged public-only context: 207 files, exactly two validated public keys, no credential config; Docker-equivalent dotnet publish using the existing flags and Hidi --help passed. Published Hidi remains 2.12.2/net8.0; both strong-name identities match their existing public keys.
• Exact-head v2 PR CI run 37963211352 passed for 34aae7388fcf02b0e0e83d845cf7c9101d5734f8: actual no-push/no-secret Docker image build and container --help, Windows executable, 91 Hidi tests, 1,279 OData tests, and pack/install/transform smoke checks. Continuous Deployment was skipped. This demonstrates optional-mount compatibility, not credentialed official feed/signing/publishing.
• Main fix(hidi): authenticate official Docker restores via BuildKit secrets #890's actual no-secret Docker check also passed in run 37961910809; this v2 PR has its own independent proof above.

Release safety

hidiPublishingEnabled remains false. No image/package/release was published, private signing key added, permission granted, environment created, or shared Docker daemon/emulation started. Official pipeline 759 remains awaiting owner-controlled Azure authorization; credentialed official restore/signing/publishing has not been verified. Normal owner review and checks are required; do not auto-merge or enable publishers as part of this PR.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud