chore(routing): migration to `auto_route`

[fres-sudo]

🎯 Description

Migrate from the default Flutter routing system to auto_route package for better type-safe navigation, code generation, and improved developer experience.

Closes: #452

📱 Changes

• [x] Update pubspec.yaml dependencies
• [x] Create router configuration
• [ ] Annotate existing pages
• [ ] Generate routing code
• [x] Update main.dart
• [ ] Replace all navigation calls
• [ ] Test all navigation flows
• [ ] Update CI/CD pipeline for build_runner
• [ ] Update development documentation
• [ ] Configure IDE/editor for generated files

🧪 Testing Instructions

Behaviour

1. Run the build_runner with fvm dart run build_runner watch --delete-conflicting-outputs in order to generate the routes
2. Check if the routing flows are corrects

🔍 Checklist for reviewers

• [x] Code is formatted correctly
• [x] Tests are passing
• [x] New tests are added (if needed)
• [x] Style matches the figma/designer requests
• Tested on:
  • [x] iOS
  • [ ] Android