Update module for DKAN 4.x compatibility

[dcgoodwin2112]

Summary

Updates Datastore Data Preview for DKAN 4.x compatibility.

• Updates Drupal/DKAN module dependencies to DKAN 4 namespaces (dkan_common, dkan_datastore, dkan_metastore)
• Updates datastore/common/metastore PHP namespaces used by services, controllers, and tests
• Adds DKAN 4 metastore response handling via RootedJsonData normalization
• Keeps support for resolving distribution UUIDs to {identifier}__{version} datastore resource IDs
• Updates README, agent instructions, and lightweight architecture docs for DKAN 4.x behavior

Testing

• Run unit tests
• Enable the module on a DKAN 4.x site
• Confirm a dataset node with an importable/tabular distribution renders a data preview table.
• Confirm the dataset edit form shows a “Preview data” link beside tabular distribution  downloadURL  fields.
• Confirm sort, pager, and page-size interactions update the preview table without a full page reload.

Co-authored-by: Copilot

[dcgoodwin2112]

We added getdkan/rooted-json-data as a dev dependency because DKAN 4’s MetastoreService::get() is typed to return RootedData\RootedJsonData, and the module’s standalone PHPUnit setup needs that class available when mocking/testing MetastoreService.