Moves the language select into the same `grid sm:grid-cols-2` row as
date of birth and drops the standalone language wrapper plus its
`sm:max-w-xs` clamp. The profile form now carries a uniform two-cell
rhythm from top to bottom instead of alternating between paired and
single-cell rows. Updates the mobile-consistency e2e assertion to match
the new contract: dob + language MUST share a grid row.
Marc-André Bombeck
a04e119cac