feat(scripts/data-resources): merge tree + add parent_path filter

- Backend: GET /api/v1/data-resources accepts parent_path; LIKE
  '{ws_id}/%/{escaped}/%' AND NOT LIKE '{ws_id}/%/{escaped}/%/%' on
  StorageObjects.object_key (workspace-wide, escapes _ and %, mirrors
  list_scripts parent_path semantics). 13 new tests in
  test_resources.py (helper unit / SQL compile / SQLite behavioral).
- Frontend: listResources gains parentPath arg, propagated through
  WorkspaceBoundApi + AuthContext binding. WorkspaceTreeGroup title
  count and ScriptExplorer header count now include dataResources.
  memberScriptGroups backfills data-only owners so users with only
  data resources still render a group. loadDataResources accepts an
  optional parentPath, default empty preserves prior behavior.

frontend/app/features/platform/WorkspaceTree.tsx

@@ -150,7 +150,7 @@ export function WorkspaceTreeGroup({
         <Icon name="chevron" size={14} />
         <Icon name="folder" size={17} />
         <span>{title}</span>
-        <em>{scripts.length}</em>
+        <em>{scripts.length + (dataResources ?? []).length}</em>
       </button>
       {open && (
         <div className="tree-group__items">