init: hgmj server initial commit

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

common/maths/max.go

@@ -0,0 +1,16 @@
+package maths
+
+import "math"
+
+func Max(input Float64Data) (max float64, err error) {
+	if input.Len() == 0 {
+		return math.NaN(), EmptyInputErr
+	}
+	max = input.Get(0)
+	for i := 1; i < input.Len(); i++ {
+		if input.Get(i) > max {
+			max = input.Get(i)
+		}
+	}
+	return max, nil
+}