Function FilterCachedFKRows

In-memory filter/sort over cached rows for the FK dropdown.

• Empty query → returns the first limit rows sorted ascending by the formatted name field (the "focus-show" behavior).
• Non-empty query → returns every row whose formatted name field contains the query as a case-insensitive substring (no limit; the full match set).

getName extracts the raw name-field value for a row; formatting + comparison are handled here so callers don't duplicate the rules.