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/withExcludeMedia3Dash.ts

@@ -0,0 +1,36 @@
+import { type ConfigPlugin, withAppBuildGradle } from "expo/config-plugins";
+
+const withExcludeMedia3Dash: ConfigPlugin = (config) => {
+  return withAppBuildGradle(config, (config) => {
+    const contents = config.modResults.contents;
+
+    // Add exclusion for duplicate media3 modules before dependencies block
+    const exclusionBlock = `
+configurations.all {
+    // Exclude duplicate media3 modules to avoid conflict between react-native-video and react-native-track-player
+    exclude group: 'androidx.media3', module: 'media3-exoplayer-dash'
+    exclude group: 'androidx.media3', module: 'media3-exoplayer-smoothstreaming'
+    exclude group: 'androidx.media3', module: 'media3-exoplayer-rtsp'
+}
+`;
+
+    // Check if exclusion already exists
+    if (contents.includes("media3-exoplayer-dash")) {
+      return config;
+    }
+
+    // Insert before the dependencies block
+    const dependenciesIndex = contents.indexOf("dependencies {");
+    if (dependenciesIndex !== -1) {
+      config.modResults.contents =
+        contents.slice(0, dependenciesIndex) +
+        exclusionBlock +
+        "\n" +
+        contents.slice(dependenciesIndex);
+    }
+
+    return config;
+  });
+};
+
+export default withExcludeMedia3Dash;