Copilot review: the comments offered "a nullable number the user cleared" as a
way to get an explicit `null` into this field. Clearing the box reports
`undefined` — `toNumericValue("")` says so, and an existing test pins it — so
the only way `null` arrives is from parent state: a value received from the
server, restored from a deep link, or written by a caller for a nullable
schema. Say that in all three places instead.
Signed-off-by: cliffhall <cliff@futurescale.com>
a945fb71c6