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/external-link.tsx

@@ -0,0 +1,25 @@
+import { Href, Link } from "expo-router"
+import { openBrowserAsync, WebBrowserPresentationStyle } from "expo-web-browser"
+import { type ComponentProps } from "react"
+
+type Props = Omit<ComponentProps<typeof Link>, "href"> & { href: Href & string }
+
+export function ExternalLink({ href, ...rest }: Props) {
+	return (
+		<Link
+			target="_blank"
+			{...rest}
+			href={href}
+			onPress={async (event) => {
+				if (process.env.EXPO_OS !== "web") {
+					// Prevent the default behavior of linking to the default browser on native.
+					event.preventDefault()
+					// Open the link in an in-app browser.
+					await openBrowserAsync(href, {
+						presentationStyle: WebBrowserPresentationStyle.AUTOMATIC,
+					})
+				}
+			}}
+		/>
+	)
+}