Added src/TemplateEngine/Directory.Build.props:
- Chains to repo root props via GetPathOfFileAbove
- StrongNameKeyId: MicrosoftAspNetCore
- GenerateDocumentationFile: true
- StyleCop.Analyzers + PublicApiAnalyzers package references
- Suppressed RS0016/RS0041 (Public API analyzer version differences)
- Suppressed NU5105/NU5128/NU5100/NU5118/0419/0649

Added src/TemplateEngine/.editorconfig:
- Migrated StyleCop rule suppressions from dotnet/templating
- Downgraded IDE0005 to suggestion (multi-target implicit usings conflict)

Root Directory.Build.props:
- Added TemplateEngineRoot, TemplatesDir, NetFrameworkMinimum properties

Updated all TE csproj/props files:
- Replaced $(SrcDir) with $(TemplateEngineRoot)
- Replaced $(ToolsDir) with $(TemplateEngineRoot)Tools/
- Replaced $(TestDir) with $(RepoRoot)test/TemplateEngine/

Now that TemplateEngine source is in-repo, convert external package
references to in-tree project references:

src/Cli/Microsoft.TemplateEngine.Cli:
- Microsoft.TemplateEngine.Edge → ProjectReference
- Microsoft.TemplateSearch.Common → ProjectReference

src/Cli/dotnet:
- Microsoft.TemplateEngine.Orchestrator.RunnableProjects → ProjectReference

test/Microsoft.TemplateEngine.Cli.UnitTests:
- Microsoft.TemplateEngine.Mocks → ProjectReference
- Microsoft.TemplateEngine.TestHelper → ProjectReference
- Microsoft.TemplateEngine.Orchestrator.RunnableProjects → ProjectReference

test/dotnet-new.IntegrationTests:
- Microsoft.TemplateEngine.TestHelper → ProjectReference
- Microsoft.TemplateEngine.Authoring.TemplateVerifier → ProjectReference

test/dotnet.Tests:
- Microsoft.TemplateEngine.Mocks → ProjectReference
- Microsoft.TemplateEngine.TestHelper → ProjectReference

Added /src/TemplateEngine/ folder with 8 source projects
Added /src/TemplateEngine/Tools/ folder with 8 tool projects
Added 19 TemplateEngine test projects to /test/ folder

test/Directory.Build.props:
- Added _IsTemplateEngineTestProject detection property
- StrongNameKeyId: MicrosoftAspNetCore for TE test projects (InternalsVisibleTo)
- GenerateProgramFile: true for TE test projects (different test runner)
- Suppressed IDE0005, CS0649, CA2016, CA5394, CA1802 for TE tests

test/Directory.Build.targets:
- Scoped FluentAssertions/TestFramework global usings to non-TE tests
- Scoped Common/Program.cs inclusion to non-TE tests
- TE test projects get minimal Xunit global using only

test/UnitTests.proj:
- Added TemplateEngine test template assets for Helix payload

- Removed duplicate PackageVersion entries (FakeItEasy, Verify.DiffPlex,
  Verify.XUnit) that conflicted with eng/dependabot/Packages.props
- Bumped Microsoft.IO.Redist 6.0.1 → 6.1.0 (MSBuild transitive dependency)
- Restored Microsoft.DotNet.Build.Tasks.Templating (Arcade package, not TE)
  to Version.Details.xml, Version.Details.props, and Directory.Packages.props
- Fixed template.json schema path in RunnableProjects.UnitTests to use
  $(TemplateEngineRoot) instead of $(SolutionDir)
- Fixed Authoring.Tasks.IntegrationTests Compile include to use
  $(TemplateEngineRoot)Tools\Shared instead of broken relative path

- Move NetFrameworkMinimum override from repo root to TemplateEngine scope
- Remove signing exclusions from eng/Signing.props (Arcade handles non-shipping)
- Inline package versions alphabetically in Directory.Packages.props
- Fix Version.Details.xml formatting
- Restore full .editorconfig (rules aren't covered by root editorconfig)
- Remove redundant ExcludeFromSourceOnlyBuild (inherited from parent)
- Move TemplateEngine test config into test/TemplateEngine/Directory.Build.props
  and test/TemplateEngine/Directory.Build.targets
- Restore test/Directory.Build.props and test/Directory.Build.targets to original
  state (no TE-specific conditioning)
- Remove only the global usings that TE tests don't reference
  (FluentAssertions, Microsoft.NET.TestFramework.*)

- Inline TemplateEngineRoot/TemplatesDir properties in Directory.Build.props
- Add TODO comment for RS0016/RS0041 PublicAPI analyzer suppression
- Simplify test/TemplateEngine/Directory.Build.targets
- Update TemplateEngine.slnf to be a filter over sdk.slnx
- Remove stale Microsoft.TemplateEngine.sln

- Restore all original projects in TemplateEngine.slnf that were
  inadvertently removed (Win32.Msi, NativeWrapper, SdkResolver,
  TemplateLocator.Tests)
- Add template_feed/Microsoft.TemplateEngine.Authoring.Templates to slnf
- Add TODO comments for migrating NetFrameworkMinimum to
  NetFrameworkToolCurrent in both src and test Directory.Build.props

Add TemplateEngineTestRoot property in Directory.Build.props pointing to
test\TemplateEngine\. Replace all test/TemplateEngine/ references
in csproj files with  for consistency with the
 pattern used for source projects.

Replace relative paths (..\TemplateEngine\...) with
in dotnet-new.IntegrationTests, dotnet.Tests, and Cli.UnitTests for
consistency with TE-internal project references.

- Add Directory.Build.props/targets in test_templates/ to opt out of CPM
  (test templates are test assets with hardcoded PackageReference versions)
- Fix TemplateEngineTestAssets paths in UnitTests.proj to include the
  TemplateEngine/ subdirectory prefix

The Newtonsoft → System.Text.Json migration changed the error message
format when parsing corrupted JSON settings files. Update the Verify
snapshots to match the new STJ exception message.

The following projects were duplicated with XunitV3 suffixes to support
xunit v3 testing while the main codebase was still on xunit v2. Now that
the xunit v3 migration is complete, the originals are v3 and these
variants are redundant:

- Microsoft.TemplateEngine.Mocks.XunitV3
- Microsoft.TemplateEngine.TestHelper.XunitV3
- Microsoft.TemplateEngine.Authoring.TemplateVerifier.XunitV3
- Microsoft.TemplateEngine.Authoring.TemplateApiVerifier.XunitV3
- Microsoft.TemplateEngine.Authoring.TemplateVerifier.IntegrationTests.XunitV3
- Microsoft.TemplateEngine.Authoring.TemplateVerifier.UnitTests.XunitV3

Verified no other repos in the VMR reference the v2 variants.

Now that the SDK repo has completed the xunit v3 migration, update
the original templating engine projects to use xunit v3 directly:

  keeping only the v3 code paths
- Replace xunit v2 package references with v3 equivalents:
  - xunit.abstractions -> xunit.v3.extensibility.core
  - xunit.extensibility.execution -> xunit.v3.extensibility.core
  - Xunit -> xunit.v3.assert + xunit.v3.extensibility.core
  - Verify.Xunit / Verify.XUnit -> Verify.XunitV3
- Update using Xunit.Abstractions -> using Xunit / using Xunit.Sdk
- Implement additional ITestOutputHelper members (Write, Output)
  required by xunit v3 in TestOutputLogger
- Remove dead DummyMethod from VerificationEngine.cs
- Update Verify.XunitV3 version to 28.12.0 in dependabot/Packages.props

Add ApprovalsDirectory and SnapshotsDirectory properties to TestBase
so all test projects use a single definition instead of repeating
Path.Combine(AppContext.BaseDirectory, ...) at every call site.

Co-authored-by: Copilot <[email protected]>

Replace raw AppContext.BaseDirectory + test_templates path with the
existing TestBase helper property for consistency.

Co-authored-by: Copilot <[email protected]>

- Add SetupNuGetConfigForPackagesLocation helper to TestBase
- Remove unnecessary TestTemplates ProjectReferences (CLI, TemplateVerifier,
  TemplateLocalizer) — tests access templates via TestBase.TestTemplatesLocation
- TemplateLocalizer: link Shared/TestBase.cs and use TestTemplatesLocation
- Reduce Directory.Build.targets Using removes from 6 to 2 (only the ones
  with actual type conflicts remain)

Co-authored-by: Copilot <[email protected]>

$(Version) is empty when the GeneratedText property is evaluated because
SDK versioning targets haven't been imported yet. Use a placeholder in
GeneratedText and substitute $(Version) inside the AddGeneratedFile
target where it is available.

Co-authored-by: Copilot <[email protected]>

The TemplateEngine test Directory.Build.props was overriding GenerateProgramFile
to true, but this is unnecessary because xUnit v3's _XunitGenerateEntryPoint
target automatically generates the entry point for test projects. This aligns
TemplateEngine tests with the rest of the SDK test projects which rely on
the repo-root setting of GenerateProgramFile=false.

Co-authored-by: Copilot <[email protected]>

The Approvals files were included as both Content and None items. The Content
include is redundant since the None include with CopyToOutputDirectory is
sufficient to copy files to the output directory.

Co-authored-by: Copilot <[email protected]>

…imons/sdk into merge-templating-phase2