Redesign explore search and inline top-bar search box

- Explore: replace per-kind colored badges/tints in search results
  with the app's neutral accent, add an always-visible Usuarios chip,
  and keep the top-result type label as plain text
- Move SearchBox into TopBar/MobileHeader as an inline debounced
  search form, dropping the standalone SearchBox component
- Sync design handoff artboards with the current search UI

web-player/src/lib/components/ui/SectionHeading.svelte

@@ -12,7 +12,7 @@
 </script>
 
 {#snippet heading()}
-	<h2 class="font-display text-[17.5px] font-semibold tracking-[-0.025em] text-fg">
+	<h2 class="font-display text-[17.5px] font-medium tracking-[-0.025em] text-fg">
 		{title}
 	</h2>
 	{#if subtitle}