fix(home): swap Because-you-listened rail to AlbumRow under 696 px (#520)

* fix(home): swap Because-you-listened rail to AlbumRow under 696 px

The hero-style BecauseCards are tuned for full-rail widths (3 cards at
1052 px+, 2 cards at 696-1051 px). Below that the cards stretched
full-width with a fixed 160 px cover stuck on the left and centred text
floating in a wide empty area — looked like three over-sized banners
stacked vertically instead of a compact recommendation rail.

A `ResizeObserver` on the rail wrapper now watches the container width
and below 696 px renders a standard `AlbumRow` (which is already
perf-tuned for narrow rails: artwork budget, viewport windowing, scroll
paging). Wide layouts keep the unchanged hero card layout, so the
mainstage view at full width is identical to before.

* docs(changelog): add Because-you-listened narrow-layout fix entry

src/styles/components.css

@@ -13916,7 +13916,7 @@ html[data-perf-disable-home-artwork-clip="true"] .home-lite-artwork .song-card-c
 /* Hide the 3rd card only inside the 2-column range, so:
      >= 1052px (3 cols)  -> 3 cards in one row
      696-1051px (2 cols) -> 2 cards in one row, orphan dropped
-     <  696px  (1 col)   -> 3 cards stacked, orphan welcome
+   Below 696px the rail switches to a standard AlbumRow in JS — no layout here.
    Math: 3*340 + 2*16 = 1052 (3-col cutoff), 2*340 + 1*16 = 696 (2-col cutoff). */
 @container (min-width: 696px) and (max-width: 1051px) {
   .because-card-grid > :nth-child(n+3) {