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/pages/[...lang].astro

@@ -1,7 +1,6 @@
 ---
 import { site, HEAD_FONTS } from "../data/site";
 import { ui, LANGS, LANG_LABEL, LANG_PATH, LANG_REGISTER_PATH, LANG_ACCOUNT_PATH, type Lang } from "../i18n/ui";
-import Creeper from "../components/Creeper.astro";
 import PixelIcon from "../components/PixelIcon.astro";
 import ServerCard from "../components/ServerCard.astro";
 import PlayerRoster from "../components/PlayerRoster.astro";
@@ -66,7 +65,7 @@ const dustBits = Array.from({ length: 16 }, (_, i) => {
     <header class="nav">
       <div class="wrap nav-in">
         <a class="brand" href="#top">
-          <Creeper />
+          <img class="brand-logo" src="/ulicraft-logo-mini.svg" alt="" width="34" height="34" />
           <span class="name">ULICRAFT</span>
         </a>
         <nav class="nav-links">
@@ -252,7 +251,7 @@ const dustBits = Array.from({ length: 16 }, (_, i) => {
     <footer class="footer">
       <div class="wrap footer-in">
         <a class="brand" href="#top">
-          <Creeper />
+          <img class="brand-logo" src="/ulicraft-logo-mini.svg" alt="" width="34" height="34" />
           <span class="name">ULICRAFT</span>
         </a>
         <div class="footer-links">