Monitor Git branch changes to keep trust sharing consistent;

[Hefaistos68]

Refactored BuildBlockDialogViewModel to allow an optional user trust store path override and updated related tests for isolation. Enhanced SolutionMonitorService to watch for Git HEAD changes, handling submodules and worktrees, and re-apply trust sharing preferences on HEAD updates. Git watcher is now started and stopped with solution lifecycle events.

Note: only for the Visual Studio extension.

[Copilot]

Pull request overview

This PR updates the Visual Studio extension to keep “trust sharing” behavior consistent across Git branch switches by (1) allowing the build-block dialog view model to use an optional user trust store path override (improving test isolation) and (2) adding a Git HEAD file watcher that re-applies trust-sharing preferences when HEAD changes.

Changes:

• Added an optional userTrustPath override to BuildBlockDialogViewModel to control which user trust store is used.
• Updated BuildBlockDialogViewModel unit tests to use a temp, per-test trust store file instead of the host’s default user trust store.
• Enhanced SolutionMonitorService to start/stop a Git HEAD watcher with the solution lifecycle and re-apply trust-sharing preferences on HEAD updates (including worktrees/submodules via .git resolution).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 6 comments.

File	Description
MSBuildGuard.VisualStudio/ToolWindows/BuildBlockDialogViewModel.cs	Adds a constructor overload to allow overriding the user trust store path used for merged trust evaluation.
MSBuildGuard.VisualStudio/Services/SolutionMonitorService.cs	Introduces a FileSystemWatcher on Git HEAD and ties it to solution open/close lifecycle events.
MSBuildGuard.VisualStudio.Tests/ToolWindows/BuildBlockDialogViewModelTests.cs	Refactors tests to use an isolated trust store path and validate trust impact on risk score.