bug(datastar): `DatastarRequestCancellation` has invalid enum values and case mismatch

## Description `DatastarRequestCancellation` has two problems: ### 1. Invalid `Cleanup` value The current implementation uses `Auto` and `Disabled`, but also accepts arbitrary strings as `Custom(Js(...))`. The previous implementation had a `Cleanup` variant — however, the Datastar protocol defines only: ``` requestCancellation?: 'auto' | 'disabled' | AbortController ``` There is no `cleanup` value in the Datastar specification. **Source**: [Datastar `FetchArgs` type](https://github.com/starfederation/datastar/blob/main/library/src/plugins/actions/fetch.ts) ### 2. PascalCase vs lowercase mismatch The `Schema` transform encodes/decodes `"Auto"` and `"Disabled"` (PascalCase), but Datastar expects lowercase `"auto"` and `"disabled"`. ## Current code ```scala implicit val schema: Schema[DatastarRequestCancellation] = Schema[String].transform[DatastarRequestCancellation]( { case "Auto" => Auto case "Disabled" => Disabled case other => Custom(Js(other)) }, { case Auto => "Auto" // Bug: should be "auto" case Disabled => "Disabled" // Bug: should be "disabled" case Custom(value) => value.value }, ) ``` ## Expected Encode/decode should use lowercase strings matching the Datastar protocol: ```scala { case "auto" => Auto case "disabled" => Disabled case other => Custom(Js(other)) }, { case Auto => "auto" case Disabled => "disabled" case Custom(value) => value.value }, ``` ## File `zio-http-datastar-sdk/src/main/scala/zio/http/datastar/model/DatastarRequest.scala`