explorer: swap wordmark for compass logo, drop 'Explorer' suffix

The new wordmark already includes 'Cryptographic Triangles Explorer'
on three lines, so the inline 'Explorer' text next to the header
logo is redundant. Logo height bumped h-9 -> h-10 for better read.

New wordmark: 300x63 PNG (compass triangle + wordmark)
Old wordmark: 801x167 PNG (text-only wordmark)

src/routes/+layout.svelte

@@ -29,8 +29,7 @@
 		<div class="max-w-7xl mx-auto px-4 py-3">
 			<div class="flex items-center justify-between gap-4 flex-wrap">
 				<a href="/" class="flex items-center gap-2 shrink-0">
-					<img src="/triangles-wordmark.png" alt="Cryptographic Triangles" class="h-9 w-auto" />
-					<span class="text-tri-muted text-sm font-semibold hidden sm:inline">Explorer</span>
+					<img src="/triangles-wordmark.png" alt="Cryptographic Triangles" class="h-10 w-auto" />
 				</a>
 				<SearchBar />
 			</div>