chore(hub): remove chakra mandala backdrop for demo

Drops the column of seven chakra SVG <img> elements that rendered
faintly behind the tile grid. The chakra-themed colours and module
ordering remain (lower-chakra modules at the bottom, higher at the
top) — only the explicit mandala imagery is gone.

Reasoning for demo specifically: the symbolism was reading as too
overtly spiritual for a first-impression audience that doesn't have
the context. The grid + glow palette alone communicates the
hierarchy.

The SVG files in public/chakras/ are kept on disk so the previous
look can be restored with one Edit if we want it back.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/pages/Hub.vue

@@ -107,15 +107,6 @@ function notImplemented() {
           rgba(185, 28, 28, 0.10) 100%);
     "
   >
-    <!-- Faint chakra mandala column behind tiles (peek through translucent tiles) -->
-    <div class="absolute inset-x-0 top-0 bottom-16 flex flex-col justify-around items-center py-4 pointer-events-none">
-      <img v-for="svg in ['sahasrara.svg','ajna.svg','vishuddha.svg','anahata.svg','manipura.svg','swadhisthana.svg','muladhara.svg']"
-        :key="svg"
-        :src="`/chakras/${svg}`"
-        class="w-32 h-32 sm:w-40 sm:h-40 opacity-90"
-      />
-    </div>
-
     <!-- Main grid -->
     <div class="relative w-full max-w-2xl mx-auto px-4 pt-6 pb-2 flex-1 flex flex-col min-h-0">
       <h1 class="text-2xl font-light text-center text-foreground/90 mb-1 tracking-wide">aiolabs</h1>