feat: initialize voice-mobile React Native app with NativeWind v5

- Created new Expo app with SDK 54+ and Expo Router
- Installed and configured NativeWind v5 for Tailwind styling
- Upgraded voice-assistant to React 19 for consistency
- Kept voice-mobile outside workspace to avoid Metro bundler conflicts
- Disabled React Compiler experimental feature for stability

Setup includes:
- postcss.config.mjs with Tailwind PostCSS plugin
- global.css with Tailwind and NativeWind imports
- metro.config.js with NativeWind wrapper
- lightningcss pinned to 1.30.1 for stability

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

packages/voice-mobile/components/ui/icon-symbol.tsx

@@ -0,0 +1,41 @@
+// Fallback for using MaterialIcons on Android and web.
+
+import MaterialIcons from '@expo/vector-icons/MaterialIcons';
+import { SymbolWeight, SymbolViewProps } from 'expo-symbols';
+import { ComponentProps } from 'react';
+import { OpaqueColorValue, type StyleProp, type TextStyle } from 'react-native';
+
+type IconMapping = Record<SymbolViewProps['name'], ComponentProps<typeof MaterialIcons>['name']>;
+type IconSymbolName = keyof typeof MAPPING;
+
+/**
+ * Add your SF Symbols to Material Icons mappings here.
+ * - see Material Icons in the [Icons Directory](https://icons.expo.fyi).
+ * - see SF Symbols in the [SF Symbols](https://developer.apple.com/sf-symbols/) app.
+ */
+const MAPPING = {
+  'house.fill': 'home',
+  'paperplane.fill': 'send',
+  'chevron.left.forwardslash.chevron.right': 'code',
+  'chevron.right': 'chevron-right',
+} as IconMapping;
+
+/**
+ * An icon component that uses native SF Symbols on iOS, and Material Icons on Android and web.
+ * This ensures a consistent look across platforms, and optimal resource usage.
+ * Icon `name`s are based on SF Symbols and require manual mapping to Material Icons.
+ */
+export function IconSymbol({
+  name,
+  size = 24,
+  color,
+  style,
+}: {
+  name: IconSymbolName;
+  size?: number;
+  color: string | OpaqueColorValue;
+  style?: StyleProp<TextStyle>;
+  weight?: SymbolWeight;
+}) {
+  return <MaterialIcons color={color} size={size} name={MAPPING[name]} style={style} />;
+}