Accordion: no flat/line variant, no per-instance closed control; items prop is string-only

[MhaWay]

Found cloning ggally.net FAQ. AccordionRenderer always renders boxed cards (rounded-card border bg p-4 + space-y-3 wrapper) with a single openFirst bool; no closed-set knob for flat borderless rows, item spacing, per-item initial state, plus/chevron icon. twClasses reach only the wrapper. Also items is a string of title|content lines: an array renders literal Array ((string) cast) — accept arrays or validate.