[Webview] DOM storage (localStorage/sessionStorage) disabled on ArkWeb

[Islatri]

Linked PR

1. feat(plugin-webview): support domStorageAccess for ArkWeb DOM storage #77

Problem

ArkWeb disables DOM storage by default unless .domStorageAccess(true) is
explicitly set on the Web() component. The ohos.webview plugin never sets
it, so:

• window.localStorage / sessionStorage are null
• frontends throw Cannot read properties of null (white screen)
• token / settings / history cannot be persisted

Android and iOS WebViews enable DOM storage by default, so this is a platform
gap every webview consumer hits on OpenHarmony.

Proposed change

Add a dom_storage_access option to WebviewCreateRequest, thread it through
the named N-API ohos.webview.CreateRequest into the ArkTS WebviewPlugin,
and call .domStorageAccess(...) on the Web() component — defaulting to
enabled to match Android/iOS.

Affected

• crates/plugin-webview/src/lib.rs (Rust facade)
• plugins/webview/src/main/ets/WebviewPlugin.ets (ArkTS HAR)

References

arkts-basic-components-web-attributes.md