{{-- One M3 list item: a headline with what leads it, what supports it and what trails it. `title` (or the slot) is the body-large headline; `overline` sits above it (label-small), `description` under it (body-medium, up to two lines). The leading element is one of `icon`, `avatar` (an image URL, or initials in primary-container), `image` (a 56px thumbnail) or `video`, or a `leading` slot (a checkbox, a switch). The trailing element is `trailing` text (label-small), `icon-right`, or an `end` slot for controls (a menu, a switch). One-, two- and three-line items (`data-md-lines`, 56, 72, 88px) follow from what is given, 16px between the item and what leads or trails it, and a three-line item top-aligns rather than centring — M3 aligns an item middle "by default, top-aligned if the item is 88dp+ or has 3+ lines of text". Its icons are 24px, or 20px in a `segmented` list, which is M3 Expressive's (ListTokens, androidx Compose Material 3, Apache-2.0). `video` is M3's leading media in its landscape size — a poster URL, or a `` holding a `