Port Layout Primitives

```[tasklist]
### Initial Port
- [x] Update namespace (to `CommunityToolkit.WinUI.Controls`)
- [x] Ignore `AdaptiveGridView` for now
- [x] Merge differences from UWP main to
- [x] WinAppSDK
- [x] Uno Platform fork
- [x] Import original doc or setup new doc
- [x] Samples
- [x] Tests
- [x] All brought over tests pass for UWP/WinAppSDK
- [x] Support for WASM via Uno Platform
```

```[tasklist]
### Known Issues / Remaining
- [x] WrapPanel Sample binding doesn't work form ItemsPanelTemplate
- [ ] UniformGrid not working properly in WASM
- [ ] ConstrainedBox sample missing as we don't have TilesBrush yet
- [ ] https://github.com/CommunityToolkit/Windows/issues/130
- [ ] https://github.com/CommunityToolkit/Windows/issues/129
- [ ] https://github.com/CommunityToolkit/Windows/issues/128
- [ ] Tests should be converted to use new test page setup over XamlReader
- [ ] Split StaggaredPanel/Layout doc and samples?
- [ ] https://github.com/CommunityToolkit/Windows/issues/131
```

## Notable Changes

- We didn't bring over `AdaptiveGridView` as it should be replaceable by the `UniformGridLayout` for `ItemsRepeater`

## Open Issues

## Future Improvements

レイアウトプリミティブのサンプルとテストに関する残りのチェックリストから始め、特に UniformGrid の WASM 問題と、欠落している ConstrainedBox サンプルに取り組んでください。XamlReader アプローチではなく、既存のテストページのセットアップを確認してください。列挙された残りの項目（リンクされた issue と、提案されているドキュメントとサンプルの分割を含む）が解決されれば完了です。

索引モデルが issue の本文から書いたものです。