Multi-Minute Interval Marker

Testing

Apply this to a 15-second chart (e.g., SOL/USDT).
Verify that thin vertical lines with "1" (grey) and "5" (yellow) appear above the candles at 4-candle (1-minute) and 20-candle (5-minute) intervals, respectively.
The numbers should be positioned above the lines, and you can toggle the markers with show1Min and show5Min.