Parallel font loading

(cherry picked from commit 10e2b05b575bbbf8b0ca5b4a336817cd902d712b)

src/alf/util/useFonts.ts

@@ -0,0 +1,8 @@
+export function useFonts() {
+  /**
+   * For native, the `expo-font` config plugin embeds the fonts in the
+   * application binary. But `expo-font` isn't supported on web, so we fall
+   * back to async loading here.
+   */
+  return [true, null]
+}