feat: improves screen clearing functionality

Updates the screen clearing function to provide a more robust cross-platform solution. It now attempts to reset text attributes on Windows and uses `shutil.which` to locate the `clear` command on Unix-like systems, falling back to ANSI escape codes if necessary.

This change improves the screen-clearing function, ensuring its effectiveness regardless of the operating system or available commands.

main.py

@@ -25,12 +25,30 @@ def get_usage() -> list[tuple]:
     return cmd_list
 
 
-def display_usage():
+def clear_screen():
     if os.name == 'nt':
+        # Windows system
+        try:
+            # try to reset the text attributes
+            kernel32 = ctypes.windll.kernel32
+            handle = kernel32.GetStdHandle(-11)  # STD_OUTPUT_HANDLE
+            kernel32.SetConsoleTextAttribute(handle, 7)
+        except Exception:
+            pass
+
         os.system('cls')
     else:
-        os.system('clear')
+        # Unix-like system
+        clear_cmd = shutil.which('clear')
+        if clear_cmd:
+            os.system(clear_cmd)
+        else:
+            # backup plan: Use ANSI escape codes (to clear and reset the screen).
+            print('\033c', end='')
 
+
+def display_usage():
+    clear_screen()
     for cmd, msg in get_usage():
         print(f"{cmd}: {msg}")