feat(branding): use Ulicraft goat logo in header, ServerCard, and server icon

- landing header + footer brand: swap the Creeper pixel-art for the
  ulicraft-logo-mini.svg goat mark.
- ServerCard fallback icon: same logo (real SLP favicon still overrides on
  a successful ping).
- minecraft: set ICON=/extras/server-icon.png + OVERRIDE_ICON so the
  in-game server-list entry and the SLP favicon use the goat logo. PNG
  ships in ./runtime (mounted /extras).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

landing/src/styles/main.css

@@ -295,6 +295,7 @@ section { position: relative; z-index: 1; }
   height: 68px;
 }
 .brand { display: flex; align-items: center; gap: 12px; text-decoration: none; color: var(--text); }
+.brand-logo { width: 34px; height: 34px; flex-shrink: 0; }
 .brand .name {
   font-family: var(--font-head);
   font-weight: 600;