Test: Multi-service scaffolding CI validation (Contoso, AppLink, Discovery)

[haiyuazhang]

🧪 Test PR — Multi-Service Scaffolding CI Validation

⚠️ Do not merge — this PR will be closed after CI validation.

Purpose

This PR validates that the scaffolding automation from #57875 works correctly across 3 different brand-new management-plane TypeSpec SDKs, using the same spec commits as their respective AutoPRs.

Services Tested

Service	Package	Spec Commit	AutoPR	Files	Gen Result
Contoso	Azure.ResourceManager.Contoso	a3fd1efe	#57746	54	✅ Build succeeded
AppLink	Azure.ResourceManager.AppLink	5bdcbdbb	#57404	115	⚠️ Build error in generated code (CS0102 duplicate member — emitter bug, not scaffolding)
Discovery	Azure.ResourceManager.Discovery	74cc90c4	#56854	249	✅ Build succeeded

How this PR was generated

For each service, an input JSON was created simulating an AutoPR trigger, then Invoke-GenerateAndBuildV2.ps1 was run with the scaffolding changes from #57875:

tsp-client init
  → Emitter generated src/Generated/ code, .csproj, .sln, metadata.json, tsp-location.yaml
  ↓
New-MgmtPackageScaffolding()        ← NEW from #57875
  → Created ci.mgmt.yml, Directory.Build.props, README.md, CHANGELOG.md,
    AssemblyInfo.cs, test project, test base/environment classes
  ↓
GeneratePackage() with gate removed  ← CHANGED in #57875
  → dotnet build → dotnet pack → Export-API.ps1

What this validates

• ✅ Scaffolding works for services with different naming patterns (single word, compound word, multi-word)
• ✅ Template placeholder substitution handles all variants correctly
• ✅ CI configuration (ci.mgmt.yml) is generated at the right path for each service
• ✅ Build/pack/API export pipeline runs for mgmt packages (previously skipped)
• ✅ AppLink's generated code build error doesn't block the pipeline (result override works)

Related PRs

• #57875 — Scaffolding automation script changes
• #57873 — Single-service test (HorizonDb)