No Error Notifications

[GowsiSM]

Errors from socket connections, file operations, and other failures don't provide clear user feedback. Users may not know when something goes wrong.

Expected Changes:
Add toast notification system
Show error toasts for failed operations
Show success toasts for important operations (file created, code run)
Include dismiss button and auto-dismiss after 5 seconds
Position toasts in non-intrusive location (top-right or bottom-right)