feat: add Babel configuration and update styles to use new theme structure

- Introduced a Babel configuration file for the app.
- Updated various components and styles to utilize the new theme structure, replacing direct color references with palette-based colors for improved consistency and maintainability.
- Adjusted styles across multiple components to align with the new theme, enhancing the overall UI experience.

packages/app/babel.config.js

@@ -0,0 +1,7 @@
+module.exports = function (api) {
+  api.cache(true);
+  return {
+    presets: ["babel-preset-expo"],
+    plugins: [["react-native-unistyles/plugin", { root: "app" }]],
+  };
+};