PersonDocumentList: empty/populated, year-range derivation across
no-date/single-year/multi-year inputs, sort toggle visibility (>1 doc),
sort-direction round trip, preview-limit + show-more expansion,
title→originalFilename fallback, no-date and no-location branches.
persons/new: PERSON vs INSTITUTION/GROUP visibility matrix
(firstName/alias/life-year fields toggle), lastName label switching
between Vorname/Nachname/Name, form-error banner, prior-form hydration,
cancel link href, fallback to PERSON for unknown personType.
24 tests across two files, hitting the 32+28 = 60 branches at the top
of the issue's leverage list.
Refs #496.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
