Render Modal as real markup; drain scripts via CaptureScript (#2742)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

shared/components/cards/BodyPlaceholder.astro

@@ -1,8 +1,4 @@
 ---
-// Equivalent of cards/body-placeholder.html (ui/svg.html inlined).
-// TODO: the ui/svg.html `border` branch (rect + inline style) is not ported —
-//       body-placeholder.html never sets it (the "border" token in the class
-//       list is just a CSS class).
 interface Props {
   width?: number
   height?: number