refactor: migrate app.config and Expo config plugins to TypeScript

Migrate the dynamic Expo config and all 12 local config plugins from
CommonJS .js to typed TypeScript:

- app.config.js -> app.config.ts (typed ConfigContext/ExpoConfig,
  behavior-identical port)
- plugins/*.js -> plugins/*.ts with `ConfigPlugin` typings from
  expo/config-plugins; plugin options are now type-checked (withGitPod)
- app.json plugin references updated to the .ts paths
- imports unified on expo/config-plugins (some plugins used the
  @expo/config-plugins alias)

Node evaluates the config at prebuild time and cannot parse TypeScript
plugin modules on its own (verified empirically: Expo transpiles
app.config.ts itself but not its imports), so the documented tsx
approach is used: `import "tsx/cjs"` at the top of app.config.ts plus
tsx as a devDependency.

Validation: resolved prebuild configs (expo config --type prebuild) are
byte-identical to the old JS config for both mobile and TV (modulo
plugin path extensions and the builtAt timestamp); full
`bun run prebuild` and `bun run prebuild:tv` pass and all Android
plugin mods are present in the generated project (media3 exclusions,
gradle properties, cast activity, network security config, alert
colors).

plugins/withTVOSAppIcon.ts

@@ -0,0 +1,31 @@
+import { type ConfigPlugin, withXcodeProject } from "expo/config-plugins";
+
+const withTVOSAppIcon: ConfigPlugin = (config) => {
+  // Only apply for TV builds
+  if (process.env.EXPO_TV !== "1") {
+    return config;
+  }
+
+  return withXcodeProject(config, async (config) => {
+    const xcodeProject = config.modResults;
+
+    const buildConfigurations = xcodeProject.pbxXCBuildConfigurationSection();
+
+    for (const key in buildConfigurations) {
+      const buildConfig = buildConfigurations[key];
+      if (
+        typeof buildConfig === "object" &&
+        buildConfig.buildSettings &&
+        buildConfig.buildSettings.PRODUCT_NAME
+      ) {
+        // Set the tvOS app icon
+        buildConfig.buildSettings.ASSETCATALOG_COMPILER_APPICON_NAME =
+          "TVAppIcon";
+      }
+    }
+
+    return config;
+  });
+};
+
+export default withTVOSAppIcon;