Fixes

os.system replaced by subprocess.run
unused vars renamed to _<var>

ui/cli.py

@@ -1,4 +1,3 @@
-from core.tracker import Tracker
 from config import ADMIN_PASSWORD
 
 
@@ -13,9 +12,10 @@ class CLI:
             self._show_main_menu()
 
     def _clear_screen(self):
+        import subprocess
         import os
 
-        os.system("cls" if os.name == "nt" else "clear")
+        subprocess.run("cls" if os.name == "nt" else "clear")
 
     def _show_main_menu(self):
         print("=" * 50)
@@ -117,7 +117,7 @@ class CLI:
         menu_items = self.tracker.get_items()
         item_list = list(menu_items.items())
 
-        for i, (item_id, item) in enumerate(item_list, 1):
+        for i, (_item_id, item) in enumerate(item_list, 1):
             print(f"{i}. {item.name} - ${item.price:.2f}")
 
         print(f"{len(item_list) + 1}. Cancel")
@@ -199,7 +199,7 @@ class CLI:
             print("No users with debt.")
         else:
             total = 0
-            for user_id, debt_info in all_debts.items():
+            for _user_id, debt_info in all_debts.items():
                 amount = debt_info["debt"]
                 print(f"{debt_info['name']:.<30} ${amount:>7.2f}")
                 total += amount
@@ -322,7 +322,7 @@ class CLI:
                 confirm = input(f"Clear ${debt_amount:.2f}? (y/n): ").strip().lower()
 
                 if confirm == "y":
-                    result = self.tracker.adjust_debt(
+                    _result = self.tracker.adjust_debt(
                         user_id, debt_amount, ADMIN_PASSWORD
                     )