Design: Quotation typographic quote poster layout

[melvincarvalho]

Design PR — edits app.js + app.css only (no app files touched).

• Quotation gets a typographic quote poster layout (class .card.quote-poster)
  • Huge opening curly quote mark in accent color at 18% opacity
  • Quotation text in large Georgia serif italic, centered
  • Attribution line with em-dash in small-caps
  • Subtle year below attribution
  • Description as a small footnote with top border
  • Generous whitespace throughout — no hero image, no generic rows
  • Dark mode support

Gate: 324 apps pass. Task: #IssDesign2_Quotation.