Refactor: Implement SmartCube renderer, improve UI styling, and fix gaps

src/workers/Cube.worker.js

@@ -0,0 +1,46 @@
+import { RubiksJSModel } from '../utils/RubiksJSModel.js';
+
+const cube = new RubiksJSModel();
+
+// Helper to send state update
+const sendUpdate = () => {
+  try {
+    const cubies = cube.toCubies();
+    // console.log('[Worker] Sending update with cubies:', cubies.length);
+    postMessage({
+      type: 'STATE_UPDATE',
+      payload: {
+        cubies
+      }
+    });
+  } catch (e) {
+    console.error('[Worker] Error generating cubies:', e);
+    postMessage({ type: 'ERROR', payload: e.message });
+  }
+};
+
+self.onmessage = (e) => {
+  const { type, payload } = e.data;
+
+  switch (type) {
+    case 'INIT':
+    case 'RESET':
+      cube.reset();
+      sendUpdate();
+      break;
+
+    case 'ROTATE_LAYER':
+      const { axis, index, direction } = payload;
+      cube.rotateLayer(axis, index, direction);
+      sendUpdate();
+      break;
+
+    case 'VALIDATE':
+      const validation = cube.validate();
+      postMessage({
+        type: 'VALIDATION_RESULT',
+        payload: { valid: validation.valid, errors: validation.errors }
+      });
+      break;
+  }
+};