Enhancement: Add Toast Notifications for Login and Signup Actions

HI @ctrixcode Currently, after a user logs in or signs up, there is no immediate visual feedback confirming the action’s success or failure. Adding toast notifications will improve the user experience by providing clear, real-time confirmation messages.

Expected Behavior

When a user successfully logs in, display a success toast such as:
“Login successful! Welcome back 👋”

When a login attempt fails, display an error toast such as:
“Invalid credentials. Please try again.”

When a user successfully signs up, display a success toast such as:
“Account created successfully! Please log in to continue.”

If signup fails (e.g., user already exists or invalid input), display an error toast message