Merge the microbuild branch from https://github.com/aarnott/Library.Template

Specifically, this merges [239883a from that repo](AArnott/Library.Template@239883a).

Author: AArnott

.github/copilot-instructions.md

@@ -52,7 +52,7 @@ dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Rele
 
 **Exclude tests with a specific trait** (skip unstable tests):
 ```bash
-dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Release -- --filter-not-trait "FailsInCloudTest=true"
+dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Release -- --filter-not-trait "TestCategory=FailsInCloudTest"
 ```
 
 **Run tests for a specific framework only**:

tools/dotnet-test-cloud.ps1

@@ -86,7 +86,7 @@ if ($isMTP) {
         --no-build `
         -c $Configuration `
         -bl:"$testBinLog" `
-        --filter-not-trait 'FailsInCloudTest=true' `
+        --filter-not-trait 'TestCategory=FailsInCloudTest' `
         --coverage-settings "$PSScriptRoot/test.runsettings" `
         @mtpArgs `
         @dumpSwitches `