[native_assets_cli] `NativeCodeAsset` and `DataAsset` should accept an `assetId` instead of `package` and `name`.

Currently there is asymmetry between hooks and runtime
* the hooks use e.g. `NativeCodeAsset(package: ..., name: ...)`
* the runtime use `@Native(assetId: '...')`

we should remove this asymmetry by only requiring an `assetId` everywhere.

Start by locating the NativeCodeAsset and DataAsset definitions in native_assets_cli, then compare their package/name construction with the runtime @Native assetId entry point. Done means both asset classes require assetId consistently and the hooks/runtime asymmetry described in the issue is removed.

Written by the indexing model from the issue text.