fix: move dio to dependencies for pub.dev publishing

Packages used in lib/ must be declared in dependencies, not dev_dependencies.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: agordn52

pubspec.yaml

@@ -21,14 +21,14 @@ dependencies:
   flutter_secure_storage: ^10.0.0
   url_launcher: ^6.3.2
   shared_preferences: ^2.5.4
+  dio: ^5.9.1
   flutter:
     sdk: flutter
 
 dev_dependencies:
   flutter_test:
     sdk: flutter
   flutter_lints: ^6.0.0
-  dio: ^5.9.1  # For testing the Dio interceptor
 
 screenshots:
   - description: The Error Stack logo.