uSync: automated nightly + release pipeline, v17.3.7 & v18.1.1 releases

Repo: KevinJump/uSync

Released v17.3.7 — save-attempt discard fixes, blueprint bulk-save fix, property-out-of-group import fix, perf tweaks
Added a publish-nightly job to package-build.yml that pushes nightly builds to the Azure Artifacts feed on every push to v18/main (previously a manual dotnet nuget push)
Nightly package versions now use {major}.{minor}.{patch}-build.{date}.{run_number} instead of GitVersion's own scheme
Fixed package-up to build with ContinuousIntegrationBuild=true, matching release.yml, so nightly and release packages build the same way
Added npm restore caching across all three GitHub Actions workflows
Found and fixed two bugs in release.yml's nuget push step (unexpanded glob, $NUGET_API_KEY referenced with bash syntax in a pwsh step) during the pipeline's first live run
Added a required-reviewer approval gate to the nuget GitHub environment before it publishes
Released v18.1.1 to NuGet — first release through the fixed automated pipeline, with a matching GitHub Release