Add NuGet package to write git.properties file

[bart-vmware]

Description

Adds a new build-time-only package, Steeltoe.Management.GitProperties.Build, that generates a git.properties file compatible with the Spring Boot Actuator format, and wires it into the existing Info actuator endpoint (GitInfoContributor) so the values are automatically exposed at runtime.

How it works

• New MSBuild tasks project (src/Management/src/GitProperties.Build) hooks into the build pipeline, auto-detected when a project references Steeltoe.Management.Endpoint (configurable via GenerateGitProperties/GitPropertiesConsumingPackageIds).
• Repository-wide info (commit id, branch, tags, remote URL, dirty state, etc.) is computed at most once per build and cached in a shared obj/git.properties.cache file at the repo root, reused by every project/TFM in a solution. The cache refreshes automatically via MSBuild incremental-build Inputs tracking (HEAD, config, packed-refs, refs/**) whenever something changes in the repo.
• Git worktrees and submodules are each treated as independent repositories with their own shared cache.
• For deployments that don't carry .git along (e.g. cf push), dotnet build -t:WriteGitPropertiesFallbackFile writes a durable fallback copy that's used automatically whenever no live .git is available.
• GitInfoContributor (runtime side) now checks next to the app's own assembly first, falling back to the current working directory, so it finds git.properties regardless of how the app is launched.

Diagnostics

Seven GITPROPS00x codes cover every place generation can be skipped or left partial (repository not found, invalid, git executable missing, incompatible version, no commits, shallow clone, dirty-state unknown) — see the package's Diagnostics table. All are forgiving by default: generation is skipped with a suppressible warning instead of failing the build, so it's safe to add this package to projects that aren't always built inside a git checkout (e.g. a Docker build stage).

Known, documented limitations

Called out explicitly in the package readme's "Good to know" section:

• File deletions inside .git (e.g. git tag -d, git fetch --unshallow) don't invalidate the shared cache by themselves — it catches up the next time something else changes.
• Changing your global git username/email isn't tracked by the shared cache either, for the same reason.

CI changes

• The test suite spawns real nested dotnet build/publish subprocesses per test, which fragments coverage data (ephemeral temp paths, duplicate <class> entries per subprocess); merge-subprocess-coverage.ps1 repairs that before upload.
• A Category=GitProperties xUnit trait (on the test project's shared base class) is used to run the tests isolated in cibuilds, which is needed because coverage is collected differently: Coverlet is unable to instrument subprocesses.
• COMMON_TEST_ARGS/SONAR_TEST_ARGS now only contain flags genuinely shared by every dotnet test invocation in each workflow; VSTest-coverage-collector-specific flags moved to their own COVERAGE_COLLECT_ARGS var, since this suite collects coverage its own way and can't use them.

Test plan

• 43 new tests in GitProperties.Build.Test, covering auto-detection, all 7 diagnostics (including both trigger paths for the 3 diagnostics that can fire for two different reasons), the shared cache (multi-project, multi-TFM, incremental build, build-time-vs-commit-time), the fallback file (including .gitignore interaction), worktrees, submodules, publish/push scenarios, and property-content correctness (branch env var fallback, non-ASCII data, multiple remotes, shallow clones).
• 1 new unit test (GitInfoContributorTest) for the runtime path-resolution change.

Quality checklist

• Your code complies with our Coding Style.
• You've updated unit and/or integration tests for your change, where applicable.
• You've updated documentation for your change, where applicable.
  If your change affects other repositories, such as Documentation and/or Samples, add linked PRs here.
• There's an open issue for the PR that you are making. If you'd like to propose a new feature or change, please open an issue to discuss the change or find an existing issue.
• You've added required license files and/or file headers (explaining where the code came from with proper attribution), where code is copied from StackOverflow, a blog, or OSS.

[github-actions]

Summary - All Code Coverage (ubuntu-latest)

Assembly	Line coverage	Branch coverage
Steeltoe.Bootstrap.AutoConfiguration	97.4%	83.3%
Steeltoe.Common	86.4%	77%
Steeltoe.Common.Certificates	97.2%	80.2%
Steeltoe.Common.Hosting	83.5%	65%
Steeltoe.Common.Http	97.4%	80.9%
Steeltoe.Common.Logging	81.1%	56.2%
Steeltoe.Common.Net	64.5%	66.6%
Steeltoe.Configuration.Abstractions	96.3%	89.4%
Steeltoe.Configuration.CloudFoundry	97.8%	92.7%
Steeltoe.Configuration.ConfigServer	91.6%	86.2%
Steeltoe.Configuration.Encryption	97.6%	87.8%
Steeltoe.Configuration.Kubernetes.ServiceBindings	95.6%	82.6%
Steeltoe.Configuration.Placeholder	93.8%	82.6%
Steeltoe.Configuration.RandomValue	93.2%	83.3%
Steeltoe.Configuration.SpringBoot	98.3%	85%
Steeltoe.Connectors	94.5%	85.6%
Steeltoe.Connectors.EntityFrameworkCore	79.7%	65.3%
Steeltoe.Discovery.Configuration	96.3%	75%
Steeltoe.Discovery.Consul	91.5%	84%
Steeltoe.Discovery.Eureka	91.6%	81.3%
Steeltoe.Discovery.HttpClients	89.9%	91.4%
Steeltoe.Logging.Abstractions	99.4%	95.6%
Steeltoe.Logging.DynamicConsole	100%	92.3%
Steeltoe.Logging.DynamicSerilog	99.1%	95.4%
Steeltoe.Management.Abstractions	100%	100%
Steeltoe.Management.Endpoint	96%	87.1%
Steeltoe.Management.GitProperties.Build	94.7%	83%
Steeltoe.Management.Prometheus	95.8%	76.9%
Steeltoe.Management.Tasks	95.2%	80%
Steeltoe.Management.Tracing	100%	75%
Steeltoe.Security.Authentication.JwtBearer	100%	93.7%
Steeltoe.Security.Authentication.OpenIdConnect	87.7%	66.6%
Steeltoe.Security.Authorization.Certificate	95.6%	61.5%
Steeltoe.Security.DataProtection.Redis	100%	****

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
91.5% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[TimHess]

LGTM