feat: implement Google OAuth support for Android and iOS

- Added support for Google OAuth with separate client IDs for Android and iOS.
- Updated `verify_google_id_token` to validate `aud` against both client IDs and check `email_verified`.
- Modified `google_oauth_handler` to accept and process the new client IDs.
- Enhanced security by enforcing explicit JWT algorithm validation.
- Updated mobile app to handle Google OAuth flow using `expo-auth-session`.
- Fixed API request to send `id_token` in snake_case as expected by the backend.
- Added necessary environment variables for Google client IDs in mobile app.
- Implemented intent filter for Google OAuth redirect in AndroidManifest.xml.

mobile/plugins/withGoogleOAuth.js

@@ -0,0 +1,50 @@
+/**
+ * Plugin local: injeta o intent filter do Google OAuth no AndroidManifest.xml
+ * durante o `expo prebuild`.
+ *
+ * Sem esse intent filter, o Android não sabe que o MeowSpool deve interceptar
+ * o redirect do Google OAuth (scheme com.googleusercontent.apps.*), fazendo o
+ * Chrome tratar a URL como pesquisa.
+ *
+ * O scheme é o reverse do Android OAuth 2.0 client ID registrado no Google Cloud Console.
+ */
+const { withAndroidManifest } = require('@expo/config-plugins');
+
+const GOOGLE_REVERSE_CLIENT_ID =
+  'com.googleusercontent.apps.724520558909-bg5a7e4u24jmis8lgg41ucs0kv0nfp1v';
+
+module.exports = function withGoogleOAuth(config) {
+  return withAndroidManifest(config, (config) => {
+    const manifest = config.modResults;
+    const activities = manifest.manifest.application?.[0]?.activity ?? [];
+
+    const mainActivity = activities.find(
+      (a) => a.$?.['android:name'] === '.MainActivity',
+    );
+
+    if (!mainActivity) return config;
+
+    // Evita duplicar o intent filter em rebuilds consecutivos
+    const alreadyAdded = (mainActivity['intent-filter'] ?? []).some((filter) =>
+      (filter.data ?? []).some(
+        (d) => d.$?.['android:scheme'] === GOOGLE_REVERSE_CLIENT_ID,
+      ),
+    );
+
+    if (alreadyAdded) return config;
+
+    mainActivity['intent-filter'] = [
+      ...(mainActivity['intent-filter'] ?? []),
+      {
+        action: [{ $: { 'android:name': 'android.intent.action.VIEW' } }],
+        category: [
+          { $: { 'android:name': 'android.intent.category.DEFAULT' } },
+          { $: { 'android:name': 'android.intent.category.BROWSABLE' } },
+        ],
+        data: [{ $: { 'android:scheme': GOOGLE_REVERSE_CLIENT_ID } }],
+      },
+    ];
+
+    return config;
+  });
+};