Twitter Sign In Added

[upahar-khatiwada]

Pull Request

What does this implement/fix?
This PR implements Twitter login using Firebase Authentication for Flutter.

• Adds signInWithTwitter function using FirebaseAuth’s TwitterAuthProvider.
• Handles login success, cancellation, and errors with appropriate SnackBar messages.
• Navigates to HomeScreen after successful login.
• Compatible with both Android and iOS, using proper SHA-1/256 keys and callback URL configuration.

Does this close any currently open issues?
Issue #21
Closes #21

Where has this been tested?

• Pixel 8 Pro

Target Platform:

• iOS
• Android
• Web
• macOS
• Linux
• Windows

Walkthrough:

• Launch app
• Click “Login with Twitter” button
• Sign in via Twitter popup
• On success, see SnackBar confirmation and navigation to HomeScreen
• On failure or cancellation, appropriate SnackBar message is shown