Adding a marriage/partnership event used a plain <select> for the spouse,
which is unusable on a large tree — you can't search, only scroll. Swap it
for the existing PersonCombobox (already used by the relationship form), which
filters by name as you type. No onCreate, so it still resolves to an existing
person id, which is what the partnership-event handler requires.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Justin Paul <justin@jpaul.me>