/quote redesign: CD's "letter" QOTD (deckle frame, wax-seal date, watermark)

Rebuilt /quote to CD's QOTD v3 — a warm letter card with a dashed deckle frame,
an overlapping wax-seal date stamp, a giant faded quote-mark watermark, the quote
in Playfair Display italic, attribution, a "What it means" note, and Copy/Share.
Wired to live /api/quote/today (date → seal, text, author/work, meaning).

Uses our HubShell (HubBar + Back + footer + account icon) per the brief. Self-
hosted Playfair Display (roman+italic, OFL) for the signature quote/watermark/
seal; Newsreader for the body serif + Hanken for sans labels (kept to our stack
to avoid font sprawl). Rose accent matches CD (#a4607a family).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/static/fonts/CREDITS.txt

@@ -9,3 +9,5 @@ License: SIL Open Font License 1.1. All self-hosted (no Google hotlink) for the
 Work Sans — Wei Huang, OFL 1.1 (Google Fonts). Latin subset, variable 400–700.
 
 Space Mono — Colophon Foundry, OFL 1.1 (Google Fonts). Latin subset, 400.
+
+Playfair Display — Claus Eggers Sørensen, OFL 1.1 (Google Fonts). Latin subset, var 500–700 + italic. (QOTD)