Fix joys regressions + self-host Work Sans for cards (Codex audit)

- Restore desktop/tablet two-up Small Joys (arrows rotate which two show); the
  swipe rail is now phone-only (≤520). One isNarrow flag drives both the DOM
  (2 vs 3 cards) and the layout, so they can't disagree.
- Contain the overflow that let the phone rail widen the whole page: min-width:0
  + max-width:100% down the chain (bento/rightcol/pair-wrap/joys-shelf/joys),
  mobile bento column to minmax(0,1fr), and overflow-x:clip on .page as a seatbelt.
- Read-time badge: overflow-wrap:anywhere + line-height so a long
  "1 min brief · ~N min full story" never causes width pressure.
- Self-host Work Sans (latin variable woff2, OFL) and apply it to the cards —
  the bolder/darker look from CD's mockup; headings stay Newsreader.

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

frontend/static/fonts/CREDITS.txt

@@ -5,3 +5,5 @@ Source: https://github.com/sharanda/manrope (via fontsource).
 hanken-var.woff2 — "Hanken Grotesk" by Alfredo Marco Pradil. License: SIL Open Font License 1.1.
 newsreader-var.woff2 / newsreader-italic-var.woff2 — "Newsreader" by Production Type (Google Fonts).
 License: SIL Open Font License 1.1. All self-hosted (no Google hotlink) for the /home3 design direction.
+
+Work Sans — Wei Huang, OFL 1.1 (Google Fonts). Latin subset, variable 400–700.