fix: Mask private key output for security when loading from arguments

Author: BethanyJep

test.py

@@ -11,4 +11,6 @@
     print("Please provide the path to the private key file as an argument.")
     sys.exit(1)
 else:
-    print(f"Private key path: {APP_PRIVATE_KEY}")
+    # Print only the first few characters as confirmation, not the entire key
+    masked_key = APP_PRIVATE_KEY[:5] + "..." if len(APP_PRIVATE_KEY) > 5 else "..."
+    print(f"Private key loaded successfully (begins with: {masked_key})")