feat: add Expo React Native client scaffold

- Expo SDK 54 / React Native 0.81 with expo-router
- Tailscale devcontainer feature for direct device connectivity
- Dev proxy for React Native DevTools access over Tailscale
- EAS build configuration for development/preview/production
- Ona automation for Expo dev server

Co-authored-by: Ona <no-reply@ona.com>

apps/aris-client/src/components/themed-view.tsx

@@ -0,0 +1,14 @@
+import { View, type ViewProps } from "react-native"
+
+import { useThemeColor } from "@/hooks/use-theme-color"
+
+export type ThemedViewProps = ViewProps & {
+	lightColor?: string
+	darkColor?: string
+}
+
+export function ThemedView({ style, lightColor, darkColor, ...otherProps }: ThemedViewProps) {
+	const backgroundColor = useThemeColor({ light: lightColor, dark: darkColor }, "background")
+
+	return <View style={[{ backgroundColor }, style]} {...otherProps} />
+}