fix(ui): properly update ArmorSlotWidget UI when setting piece from API

- Fixed set_piece() to use protection_label instead of non-existent piece_name_label
- Now updates protection display when piece is set
- Adds piece to combo if not already present
- Properly stores current_piece and calls _update_total()

ui/loadout_manager.py

@@ -651,16 +651,37 @@ class ArmorSlotWidget(QWidget):
         """Set selected armor piece."""
         if piece is None:
             self.piece_combo.setCurrentIndex(0)
+            self.current_piece = None
+            self.protection_label.setText("-")
+            self._update_total()
             return
 
-        # Find and select the piece
+        # Store the piece
+        self.current_piece = piece
+        
+        # Update protection display
+        prot_parts = []
+        if piece.protection.impact > 0:
+            prot_parts.append(f"Imp:{piece.protection.impact}")
+        if piece.protection.cut > 0:
+            prot_parts.append(f"Cut:{piece.protection.cut}")
+        if piece.protection.stab > 0:
+            prot_parts.append(f"Stab:{piece.protection.stab}")
+        self.protection_label.setText(", ".join(prot_parts) if prot_parts else "-")
+        
+        # Try to find and select the piece in combo
         for i in range(self.piece_combo.count()):
             data = self.piece_combo.itemData(i)
-            if data and data.item_id == piece.item_id:
+            if data and hasattr(data, 'item_id') and data.item_id == piece.item_id:
                 self.piece_combo.setCurrentIndex(i)
+                self._update_total()
                 return
-
-        self.piece_combo.setCurrentIndex(0)
+        
+        # Piece not in combo - add it
+        display = f"{piece.name} (API)"
+        self.piece_combo.addItem(display, piece)
+        self.piece_combo.setCurrentIndex(self.piece_combo.count() - 1)
+        self._update_total()
 
     def set_plate(self, plate: Optional[ArmorPlate]):
         """Set selected plate."""