List universal search fields

Returns every field indexed on the universal search core. All entries contribute to the aggregated text index that the query parameter matches against — per-field criteria are not supported on universal search; only the single query string is used.

Only entries with returnable: true appear on UniversalSearchHit:

• entity_gk
• guid
• entity_name
• entity_type_id
• display_desc
• score
• entity_type_name
• company_gk

The remaining entries are indexed but not stored.