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).

app.json

@@ -71,8 +71,8 @@
       ],
       "expo-router",
       "expo-font",
-      "./plugins/withExcludeMedia3Dash.js",
-      "./plugins/withTVUserManagement.js",
+      "./plugins/withExcludeMedia3Dash.ts",
+      "./plugins/withTVUserManagement.ts",
       [
         "expo-build-properties",
         {
@@ -131,17 +131,17 @@
         }
       ],
       "expo-web-browser",
-      ["./plugins/with-runtime-framework-headers.js"],
-      ["./plugins/withChangeNativeAndroidTextToWhite.js"],
-      ["./plugins/withAndroidAlertColors.js"],
-      ["./plugins/withAndroidManifest.js"],
-      ["./plugins/withTrustLocalCerts.js"],
-      ["./plugins/withGradleProperties.js"],
-      ["./plugins/withTVOSAppIcon.js"],
-      ["./plugins/withTVOSTopShelf.js"],
-      ["./plugins/withTVXcodeEnv.js"],
+      ["./plugins/with-runtime-framework-headers.ts"],
+      ["./plugins/withChangeNativeAndroidTextToWhite.ts"],
+      ["./plugins/withAndroidAlertColors.ts"],
+      ["./plugins/withAndroidManifest.ts"],
+      ["./plugins/withTrustLocalCerts.ts"],
+      ["./plugins/withGradleProperties.ts"],
+      ["./plugins/withTVOSAppIcon.ts"],
+      ["./plugins/withTVOSTopShelf.ts"],
+      ["./plugins/withTVXcodeEnv.ts"],
       [
-        "./plugins/withGitPod.js",
+        "./plugins/withGitPod.ts",
         {
           "podName": "MPVKit",
           "podspecUrl": "https://raw.githubusercontent.com/mpv-ios/MPVKit/0.41.0-av/MPVKit.podspec"