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.config.ts

@@ -0,0 +1,79 @@
+// Registers the tsx require hook so the TypeScript config plugins referenced
+// from app.json ("./plugins/*.ts") can be loaded by Node during config evaluation.
+import "tsx/cjs";
+import { execFileSync } from "node:child_process";
+import type { ConfigContext, ExpoConfig } from "expo/config";
+
+// Build metadata, injected into `extra.build` and read at runtime via
+// expo-constants (see utils/version.ts). Sources in priority order:
+// EAS cloud build → GitHub Actions → explicit EXPO_PUBLIC_* → local git → null.
+const git = (args: string[]): string | null => {
+  try {
+    return execFileSync("git", args, { stdio: ["ignore", "pipe", "ignore"] })
+      .toString()
+      .trim();
+  } catch {
+    return null;
+  }
+};
+
+const buildMeta = {
+  commit:
+    (
+      process.env.EAS_BUILD_GIT_COMMIT_HASH ||
+      process.env.GITHUB_SHA ||
+      process.env.EXPO_PUBLIC_GIT_COMMIT ||
+      git(["rev-parse", "HEAD"]) ||
+      ""
+    ).slice(0, 7) || null,
+  branch:
+    process.env.EAS_BUILD_GIT_BRANCH ||
+    process.env.GITHUB_HEAD_REF ||
+    process.env.GITHUB_REF_NAME ||
+    process.env.EXPO_PUBLIC_GIT_BRANCH ||
+    git(["rev-parse", "--abbrev-ref", "HEAD"]) ||
+    null,
+  profile:
+    process.env.EAS_BUILD_PROFILE ||
+    process.env.EXPO_PUBLIC_BUILD_PROFILE ||
+    null,
+  // GitHub Actions run number (#2098) — lets anyone map a sideloaded CI build back
+  // to its Actions run (artifacts + logs) without Expo access. Null outside CI.
+  runNumber:
+    process.env.GITHUB_RUN_NUMBER ||
+    process.env.EXPO_PUBLIC_GIT_RUN_NUMBER ||
+    null,
+  builtAt: new Date().toISOString(),
+};
+
+export default ({ config }: ConfigContext): ExpoConfig => {
+  if (process.env.EXPO_TV !== "1") {
+    config.plugins?.push("expo-background-task");
+
+    config.plugins?.push([
+      "react-native-google-cast",
+      { useDefaultExpandedMediaControls: true },
+    ]);
+
+    config.plugins?.push([
+      "expo-camera",
+      {
+        cameraPermission:
+          "Allow Streamyfin to access the camera to scan QR codes for TV login.",
+      },
+    ]);
+  }
+
+  // Only override googleServicesFile if env var is set
+  const androidConfig: { googleServicesFile?: string } = {};
+  if (process.env.GOOGLE_SERVICES_JSON) {
+    androidConfig.googleServicesFile = process.env.GOOGLE_SERVICES_JSON;
+  }
+
+  config.extra = { ...config.extra, build: buildMeta };
+
+  return {
+    ...(Object.keys(androidConfig).length > 0 && { android: androidConfig }),
+    ...config,
+  } as ExpoConfig;
+};