rename: 🌊 Engine → Emergence → 🌊 Engine (tab label shorter)

index.html

@@ -180,7 +180,7 @@
   <button class="tab active" data-tab="emergence">✨ Emergence</button>
   <button class="tab" data-tab="dtc">🔮 Time Crystal</button>
   <button class="tab" data-tab="ag">🧲 A×G Repulsion Field</button>
-  <button class="tab" data-tab="pipeline">🌊 Engine → Emergence</button>
+  <button class="tab" data-tab="pipeline">🌊 Engine</button>
 </nav>
 
 <div id="tab-emergence" class="tab-panel active">