feat: Add Pine Script implementation of Three ATR EMA indicator

pinescripts/Three_ATR_EMA.pine

@@ -0,0 +1,42 @@
+//@version=5
+indicator(title="Three ATR EMA Bands", shorttitle="3ATR EMA", overlay=true)
+
+// Inputs
+ema_length = input.int(21, "EMA Length", minval=1)
+atr_multiplier = input.float(3.0, "ATR Multiplier", step=0.1)
+show_bullish_arrows = input.bool(true, "Show Bullish Signals")
+
+// Calculate EMA
+ema = ta.ema(close, ema_length)
+
+// Calculate True Range
+tr = math.max(high - low, math.max(math.abs(high - nz(close[1])), math.abs(low - nz(close[1]))))
+
+// Calculate Bands
+upper_band = ema + (tr * atr_multiplier)
+lower_band = ema - (tr * atr_multiplier)
+
+// Bullish Signal Condition
+bullish_signal = close < ema and 
+                close[1] <= lower_band[1] and 
+                close > close[1]
+
+// Plotting
+plot(ema, "EMA", color=color.new(#00BFFF, 0))
+plot(upper_band, "Upper Band", color=color.new(#FFA500, 0), linewidth=2)
+plot(lower_band, "Lower Band", color=color.new(#32CD32, 0), linewidth=2)
+
+// Signal Arrows
+plotshape(show_bullish_arrows and bullish_signal ? low : na, 
+          "Bullish Signal", 
+          shape.triangleup, 
+          location.belowbar, 
+          color=color.new(#00FF00, 0), 
+          size=size.small)
+
+// Alerts
+alertcondition(bullish_signal, "Bullish Signal Triggered", "3ATR EMA Bullish Signal")
+
+// Strategy Calculations for Visual Reference
+if (bullish_signal)
+    strategy.entry("Bullish", strategy.long)