The sortable headers on /bookkeeping and /invoices wrap their label in a
button, and preflight's text-transform: none on buttons swallowed the
uppercase from TH_CLASS, so sorted lists showed sentence-case heads next
to every other table's uppercase idiom. Re-apply uppercase on the sort
control itself.
Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>