DSH Host Web Compat

Key features

• Keep this plugin even in the shell-APK form as a last-mile fallback for old system WebViews.
• Fixes the in-app directory picker and other RPC flows on older WebView/browser kernels.
• MuMu's bundled browser, older WebViews) lack AbortSignal.any(), which breaks the workspace directory picker's concurrent RPC cancellation (list renders empty).
• Idempotentskipped when already present.
• If you move to a native SAF picker, the page still benefits from the other polyfills.