feat: add new indicators (Decay, Edecay, MinusDi, MinusDm, PlusDi, PlusDm, Maxindex, Minindex, Sarext) and update pine scripts, core libs, validation tests, and python bindings

lib/cycles/cg/Cg.cs

@@ -295,7 +295,7 @@ public sealed class Cg : AbstractBase
                 int idx = (effectiveStart + j) % period;
                 double price = buffer[idx];
                 int weight = j + 1; // 1-based weighting
-                weightedSum += weight * price;
+                weightedSum = Math.FusedMultiplyAdd(weight, price, weightedSum);
                 sum += price;
             }
 

lib/cycles/cg/cg.pine

@@ -1,4 +1,4 @@
-// The MIT License (MIT)
+// Licensed under the Apache License, Version 2.0
 // © mihakralj
 //@version=6
 indicator("Ehlers Center of Gravity (CG)", "CG", overlay=false)