fix(themes): route remaining UI colours through theme tokens (#1014)

* fix(themes): route remaining UI colours through theme tokens

An audit found several surfaces still wired to the fixed Catppuccin
palette or hardcoded hex, so community themes could not recolour them:
the 5-star rating, the global search field, the gradient-text flourish,
badges and category-avatar text, and the What's New page + sidebar
banner. Rewire them to existing contract tokens — no new tokens, and the
built-in themes look identical (the values match). Community themes now
control these areas.

Also fixes device-sync rows referencing an undefined --bg-secondary
(they rendered with no background); they now use --bg-card.

* docs(themes): note the theme-coverage PR in the Theme Store entry

Add PR #1014 to the still-unreleased Theme Store changelog and credits
entry, alongside the other follow-ups.

src/styles/components/device-sync.css

@@ -423,7 +423,7 @@
   gap: 8px;
   height: 52px;
   padding: 0 14px;
-  background: var(--bg-secondary);
+  background: var(--bg-card);
   border-bottom: 1px solid var(--border);
   flex-shrink: 0;
 }
@@ -792,7 +792,7 @@
 
 .device-sync-browser-row:hover { background: var(--bg-hover); }
 .device-sync-browser-row.selected { background: var(--accent-dim); }
-.device-sync-browser-row.indent { padding-left: 36px; background: var(--bg-secondary); }
+.device-sync-browser-row.indent { padding-left: 36px; background: var(--bg-card); }
 .device-sync-browser-row.indent:hover { background: var(--bg-hover); }
 .device-sync-browser-row.indent.selected { background: var(--accent-dim); }