[#163 feat] : Added Chat Heads Screen for Recent Chats

[Alpha17-2]

Description

This PR introduces a new screen to the app that displays a list of chat heads, representing the latest users with whom the current user has chatted. This feature allows users to view and access their recent chats easily. Tapping on any chat head navigates the user to the inbox screen where they can chat with the other user in real-time.

Changes Made

• New Screen: Added a ChatHeadsScreen to display a list of recent chat heads.
• Navigation: Implemented navigation from the chat heads screen to the inbox screen upon tapping a chat head.
• Real-time Chat: Enabled real-time chat functionality in the inbox screen.
• UI Components: Created UI components for displaying chat heads.

Implementation Details

Chat Heads Screen

• The screen fetches the latest chats from the database and displays them as chat heads.
• Each chat head shows the user's profile picture, name, and the last message exchanged.
• Tapping on a chat head navigates to the inbox screen for that specific chat.

Inbox Screen

• The inbox screen allows users to send and receive messages in real-time.
• Utilized Firestore to listen for real-time updates to messages.

Code Changes

• Created a new widget ChatHeadsScreen to display the list of recent chats.
• Updated navigation to handle transitions from the chat heads screen to the inbox screen.
• Modified the InboxScreen to support real-time messaging.