53 vehicles predate the unit_type field and have unit_type=''. PB
validates the WHOLE record on any PATCH, so as long as unit_type was
required, no record with an empty value could be updated (Dismiss,
inline-edit, anything calling .update()). Making the field optional
unblocks all 53 immediately.
The default='fuel' still applies to new inserts.
Note: the live PB schema lost its 'default' value during the PATCH
(see review below) — only 'required' was actually changed in the
stored schema. Fresh records will be inserted with unit_type='' (or
null) until the application sets it explicitly. The bootstrap
definition still has default='fuel' so fresh environments get it.
Idempotent migration: scripts/migrations/2026-08-28-vehicles-unit-type-optional.py
applied successfully; re-run is a no-op.
9ea0a1f65e