Add XML documentation for Dalvik.SystemInterop

The `Dalvik.SystemInterop` namespace contains **85** `To be added` placeholders in source XML documentation (excluding `docs\xml\index.xml`).

```powershell
rg -n -i --glob 'Dalvik.SystemInterop/**' --glob 'ns-Dalvik.SystemInterop.xml' 'to be added' docs\xml
```

## Update log

- 2026-09-10: Refreshed the placeholder scan from **126** to **85** (reduced by **41**). Related documentation PRs: [#482](https://github.com/dotnet/android-api-docs/pull/482), [#596](https://github.com/dotnet/android-api-docs/pull/596), [#644](https://github.com/dotnet/android-api-docs/pull/644).

Start by running the provided rg scan against docs\xml to list the 85 remaining placeholders. Review the matches under Dalvik.SystemInterop and ns-Dalvik.SystemInterop.xml, then replace the placeholders with appropriate XML documentation and rerun the scan; done means no matching placeholders remain outside docs\xml\index.xml.

Written by the indexing model from the issue text.