fix variable parsing error in stop.ps1

script/stop.ps1

@@ -27,10 +27,10 @@ foreach ($port in $ports) {
                 Write-Host "  Warning: Could not stop process on port $port (PID: $processId)" -ForegroundColor Yellow
             }
         } else {
-            Write-Host "  Port $port: No process found" -ForegroundColor DarkGray
+            Write-Host "  Port ${port}: No process found" -ForegroundColor DarkGray
         }
     } catch {
-        Write-Host "  Error checking port $port: $($_.Exception.Message)" -ForegroundColor Red
+        Write-Host "  Error checking port ${port}: $($_.Exception.Message)" -ForegroundColor Red
     }
 }