refactor: unify storage config keys and refresh local dev setup

apps/lib/features/users/data/users_api.dart

@@ -1,3 +1,5 @@
+import 'dart:io';
+import 'package:dio/dio.dart';
 import 'package:social_app/core/api/i_api_client.dart';
 import 'models/user_response.dart';
 
@@ -38,6 +40,28 @@ class UsersApi {
     return UserResponse.fromJson(response.data);
   }
 
+  Future<String> uploadAvatar(File file) async {
+    final formData = FormData.fromMap({
+      'file': await MultipartFile.fromFile(
+        file.path,
+        filename: file.path.split('/').last,
+      ),
+    });
+    final response = await _client.post<Map<String, dynamic>>(
+      '$_prefix/me/avatar',
+      data: formData,
+    );
+    final payload = response.data;
+    if (payload is! Map<String, dynamic>) {
+      throw StateError('Invalid /users/me/avatar response');
+    }
+    final url = payload['url'];
+    if (url is! String) {
+      throw StateError('Missing url in /users/me/avatar response');
+    }
+    return url;
+  }
+
   Future<List<UserResponse>> searchUsers(String query) async {
     final response = await _client.post(
       '$_prefix/search',