[DEM] Option Experation Dates

[DEM] Option Expiration Dates is a calendar-based indicator that visually highlights standard monthly option expiration dates on the price chart by applying a purple background color. The indicator identifies expiration dates using the standard rule that options expire on the third Friday of each month, which it calculates by checking for Fridays (day 6 of the week) that fall between the 15th and 21st of the month. This simple yet practical tool helps traders stay aware of significant market dates when increased volatility and volume typically occur due to option contract settlements and portfolio rebalancing activities. By automatically marking these dates with a subtle purple background, the indicator eliminates the need for manual calendar tracking and ensures traders never miss these potentially impactful market events that can influence price action and trading dynamics.