[Repo Assist] eng: add NuGet cache to build and build-msix CI jobs

[github-actions]

🤖 This PR was created by Repo Assist, an automated AI assistant.

Summary

The build and build-msix jobs each ran dotnet restore without any NuGet package caching. The test job already has a cache@v4 step that populates nuget-(os)-(csproj-hash). Adding the same step to build and build-msix lets all four matrix runners reuse the already-cached packages (two build runners + two build-msix runners), skipping redundant downloads on every CI run.

Changes

• Added actions/cache@v4 step to the build job (before dotnet restore)
• Added actions/cache@v4 step to the build-msix job (before dotnet restore)

The cache key (nuget-$\{\{ runner.os }}-$\{\{ hashFiles('**/*.csproj') }}) is identical to the test job, so the cache populated during test is reused by both build jobs running on the same OS.

Test Status

CI / workflow change only — no code changes. The test job validates the build; the only risk is a stale cache on a .csproj change, which is handled by the content-hash key.

Generated by Repo Assist · ◷

To install this agentic workflow, run

gh aw add githubnext/agentics/workflows/repo-assist.md@cbb46ab386962aa371045839fc9998ee4e97ca64

---

Warning

🛡️ Protected Files — Push Permission Denied

This was originally intended as a pull request, but the patch modifies protected files: .github/workflows/ci.yml.

The push was rejected because GitHub Actions does not have workflows permission to push these changes, and is never allowed to make such changes, or other authorization being used does not have this permission. A human must create the pull request manually.

To create a pull request with the changes:

# Download the patch from the workflow run
gh run download 23878348618 -n agent-artifacts -D /tmp/agent-artifacts-23878348618

# Create a new branch
git checkout -b repo-assist/eng-ci-build-nuget-cache-2026-04-02-1537517bfdc1daf7 master

# Apply the patch (--3way handles cross-repo patches)
git am --3way /tmp/agent-artifacts-23878348618/aw-repo-assist-eng-ci-build-nuget-cache-2026-04-02.patch

# Push the branch and create the pull request
git push origin repo-assist/eng-ci-build-nuget-cache-2026-04-02-1537517bfdc1daf7
gh pr create --title '[Repo Assist] eng: add NuGet cache to build and build-msix CI jobs' --base master --head repo-assist/eng-ci-build-nuget-cache-2026-04-02-1537517bfdc1daf7 --repo openclaw/openclaw-windows-node