feat: validate user input for entity names

internal/number/number_test.go

@@ -31,3 +31,10 @@ func TestFixed(t *testing.T) {
 		})
 	}
 }
+
+func TestMax(t *testing.T) {
+	assert.Equal(t, 10., Max(9., 10.))
+	assert.Equal(t, 11., Max(11., 10.))
+	assert.Equal(t, 0, Max(-1, 0))
+	assert.Equal(t, 1, Max(1, 0))
+}