Read only the choices a picker's fallback select shows #2656

Part of #2426 (F-FRM). Found by the independent review of #2655.

Before the circuit attaches, a reference picker renders a plain select with the 200 newest entries of its target type. It gets them from IEntryDirectory.ListAsync, which reads every entry of the type. So a large type is read in full on every editor page load, once per picker.

Scope

• The select's choices come from a read that returns only the newest 200, such as a limit on the entry list or a search with no text.
• A test that a type of more than 200 entries is not read in full by the editor.

Acceptance

• Loading an editor reads at most the choices it shows for each picker.