Android Email Client App Development

I'm in need of a freelancer who can create a robust Email Client App for Android with the following features:

Core Features:
- User Authentication and Profile Management
- Email Inbox and Folder Management
- Compose, Send, and Receive Emails
- Search Functionality
- Spam Filtering
- Email Attachments and Notifications
- Calendar Integration

The app should be designed with a Single Window with Tabs layout. It must leverage Firebase for authentication and cloud storage.

Ideal Skills:
- Proficiency in Android app development
- Experience with Firebase integration
- Strong understanding of email client functionalities
- UI/UX design skills for a Single Window with Tabs layout

Please refer to the synopsis I will provide for further details. Looking forward to your bids.