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/withAndroidAlertColors.ts

@@ -0,0 +1,50 @@
+import {
+  type ConfigPlugin,
+  withAndroidColors,
+  withAndroidColorsNight,
+} from "expo/config-plugins";
+
+interface ColorResourceItem {
+  $: { name: string };
+  _: string;
+}
+
+const withAndroidAlertColors: ConfigPlugin = (config) => {
+  const setColor = (
+    colorsList: ColorResourceItem[],
+    name: string,
+    value: string,
+  ) => {
+    const existingColor = colorsList.find(
+      (item) => item.$ && item.$.name === name,
+    );
+    if (existingColor) {
+      existingColor._ = value;
+    } else {
+      colorsList.push({
+        $: { name },
+        _: value,
+      });
+    }
+  };
+
+  config = withAndroidColors(config, (config) => {
+    const colors = config.modResults;
+    const colorsList = (colors.resources.color ?? []) as ColorResourceItem[];
+    setColor(colorsList, "colorPrimary", "#000000");
+    colors.resources.color = colorsList;
+    return config;
+  });
+
+  config = withAndroidColorsNight(config, (config) => {
+    const colors = config.modResults;
+    const colorsList = (colors.resources.color ?? []) as ColorResourceItem[];
+    setColor(colorsList, "colorPrimary", "#FFFFFF");
+    colors.resources.color = colorsList;
+    return config;
+  });
+
+  return config;
+};
+
+export default withAndroidAlertColors;