Add XML documentation for Android.Hardware.Lights

The `Android.Hardware.Lights` namespace contains **142** `To be added` placeholders in source XML documentation (excluding `docs\xml\index.xml`).

Example command:

```powershell
rg -n -i --glob 'Android.Hardware.Lights/**' --glob 'ns-Android.Hardware.Lights.xml' 'to be added' docs\xml
```

## Update log

- 2026-09-10: Refreshed the placeholder scan from **136** to **142** (increased by **6**). Related documentation PRs: [#644](https://github.com/dotnet/android-api-docs/pull/644).

Start by running the provided rg command against docs\xml to enumerate the Android.Hardware.Lights files and the 142 placeholders. Read the surrounding API entries and existing documentation patterns, then replace every matching “To be added” entry; done means the namespace scan reports no remaining placeholders.

Written by the indexing model from the issue text.