fix: use indexed for loop instead of for...of for ES5 compatibility

TypeScript with target ES5 doesn't support for...of iteration over
Float64Array. Changed back to indexed for loop which is compatible
with ES5 while maintaining the same functionality.

Author: cursoragent

src/modifiers/colormodifier.ts

@@ -161,7 +161,8 @@ class ColorModifier extends Modifier {
     // Calculate min/max using a loop to avoid stack overflow for large arrays
     let minValue = Infinity;
     let maxValue = -Infinity;
-    for (const value of perAtomArray) {
+    for (let i = 0; i < perAtomArray.length; i++) {
+      const value = perAtomArray[i];
       minValue = Math.min(minValue, value);
       maxValue = Math.max(maxValue, value);
     }