style(vibe): center the ambient profile aura

frontend/src/components/VibeAura.tsx

@@ -28,12 +28,13 @@ export function VibeAura({ profile, ambient = false }: { profile: VibeProfile; a
     '--vibe-pulse': `${(4.8 - energy * 2.3).toFixed(2)}s`,
     '--vibe-orbit': `${(11 - energy * 4).toFixed(2)}s`,
     '--vibe-scale': String((0.9 + energy * 0.16).toFixed(2)),
+    '--vibe-core-opacity': ambient ? '0.38' : '1',
   } as CSSProperties;
 
   return (
     <div
       className={ambient
-        ? 'pointer-events-none absolute right-10 top-32 z-0 grid h-16 w-16 scale-[3.6] place-items-center rounded-full opacity-35'
+        ? 'pointer-events-none absolute left-1/2 top-[58%] z-0 grid h-16 w-16 -translate-x-1/2 -translate-y-1/2 scale-[7.2] place-items-center rounded-full opacity-50'
         : 'group relative grid h-16 w-16 shrink-0 place-items-center rounded-full focus:outline-none'}
       style={style}
       role="img"
@@ -43,7 +44,7 @@ export function VibeAura({ profile, ambient = false }: { profile: VibeProfile; a
       <div className="vibe-aura-halo" />
       <div className="vibe-aura-orbit vibe-aura-orbit-one" />
       <div className="vibe-aura-orbit vibe-aura-orbit-two" />
-      <div className="vibe-aura-core">
+      <div className="vibe-aura-core" style={{ opacity: 'var(--vibe-core-opacity, 1)' }}>
         <span className="vibe-aura-spark vibe-aura-spark-one" />
         <span className="vibe-aura-spark vibe-aura-spark-two" />
         <span className="vibe-aura-heart" />