Mobile combing: WOTD watermark, Entertainment card breathing, Art lightbox fit

- WOTD /word: watermark was nudged too far down last round; bring it back up to
  sit JUST below the date (clears it by a few px instead of dropping markedly).
- home3 Entertainment card: stacked on mobile it lost the height it borrowed from
  Play on desktop and felt crowded — add vertical breathing (padding + gaps), not
  as tall as desktop.
- /art lightbox: on a narrow portrait phone the framed piece (image + mat + rail)
  overflowed the viewport (rail clipped → looked distorted). Cap the image so the
  WHOLE frame fits, leaving room for the caption.

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

frontend/src/routes/home3/+page.svelte

@@ -482,5 +482,10 @@
     .joys { grid-template-columns: 1fr; }
     /* tighten the joys header so the title + dots/arrows never collide on a phone */
     .joys-head { flex-wrap: wrap; gap: 8px 12px; }
+    /* Entertainment: when stacked it loses the height it borrowed from Play on desktop,
+       so the content felt crowded. Give it room to breathe (not as tall as desktop). */
+    .moment { padding: 30px 24px; gap: 6px; }
+    .moment-mid { gap: 18px; padding: 12px 0; }
+    .moment-meta { margin-top: 18px; }
   }
 </style>