fix(obiutils): correctly unwrap interface values in min/max

Introduces an `unwrapInterface` reflection helper to dereference `interface{}`-wrapped values before type validation. Updates slice and map iteration loops in min/max functions to apply this helper, ensuring `isOrderedKind` accurately identifies underlying concrete types instead of incorrectly rejecting `reflect.Interface` elements.

pkg/obiutils/minmax.go

@@ -309,7 +309,7 @@ func saturatingSubValues(a, b reflect.Value) (reflect.Value, error) {
 func maxFromIterable(v reflect.Value) (interface{}, error) {
 	var best reflect.Value
 	for i := 0; i < v.Len(); i++ {
-		elem := v.Index(i)
+		elem := unwrapInterface(v.Index(i))
 		if !isOrderedKind(elem.Kind()) {
 			return nil, fmt.Errorf("unsupported element type: %s", elem.Kind())
 		}
@@ -324,7 +324,7 @@ func maxFromIterable(v reflect.Value) (interface{}, error) {
 func minFromIterable(v reflect.Value) (interface{}, error) {
 	var minVal reflect.Value
 	for i := 0; i < v.Len(); i++ {
-		elem := v.Index(i)
+		elem := unwrapInterface(v.Index(i))
 		if !isOrderedKind(elem.Kind()) {
 			return nil, fmt.Errorf("unsupported element type: %s", elem.Kind())
 		}
@@ -339,7 +339,7 @@ func filterMinFromIterable(v reflect.Value, minimum interface{}) (interface{}, e
 	minVal := reflect.ValueOf(minimum)
 	result := reflect.MakeSlice(v.Type(), 0, v.Len())
 	for i := 0; i < v.Len(); i++ {
-		elem := v.Index(i)
+		elem := unwrapInterface(v.Index(i))
 		if !isOrderedKind(elem.Kind()) {
 			return nil, fmt.Errorf("unsupported element type: %s", elem.Kind())
 		}
@@ -354,7 +354,7 @@ func filterMaxFromIterable(v reflect.Value, maximum interface{}) (interface{}, e
 	maxVal := reflect.ValueOf(maximum)
 	result := reflect.MakeSlice(v.Type(), 0, v.Len())
 	for i := 0; i < v.Len(); i++ {
-		elem := v.Index(i)
+		elem := unwrapInterface(v.Index(i))
 		if !isOrderedKind(elem.Kind()) {
 			return nil, fmt.Errorf("unsupported element type: %s", elem.Kind())
 		}
@@ -369,7 +369,7 @@ func filterMinFromMap(v reflect.Value, minimum interface{}) (interface{}, error)
 	minVal := reflect.ValueOf(minimum)
 	result := reflect.MakeMap(v.Type())
 	for _, key := range v.MapKeys() {
-		elem := v.MapIndex(key)
+		elem := unwrapInterface(v.MapIndex(key))
 		if !isOrderedKind(elem.Kind()) {
 			return nil, fmt.Errorf("unsupported element type: %s", elem.Kind())
 		}
@@ -384,7 +384,7 @@ func filterMaxFromMap(v reflect.Value, maximum interface{}) (interface{}, error)
 	maxVal := reflect.ValueOf(maximum)
 	result := reflect.MakeMap(v.Type())
 	for _, key := range v.MapKeys() {
-		elem := v.MapIndex(key)
+		elem := unwrapInterface(v.MapIndex(key))
 		if !isOrderedKind(elem.Kind()) {
 			return nil, fmt.Errorf("unsupported element type: %s", elem.Kind())
 		}
@@ -400,7 +400,7 @@ func maxFromMap(v reflect.Value) (interface{}, error) {
 	var best reflect.Value
 	first := true
 	for _, key := range v.MapKeys() {
-		elem := v.MapIndex(key)
+		elem := unwrapInterface(v.MapIndex(key))
 		if !isOrderedKind(elem.Kind()) {
 			return nil, fmt.Errorf("unsupported element type: %s", elem.Kind())
 		}
@@ -417,7 +417,7 @@ func minFromMap(v reflect.Value) (interface{}, error) {
 	var minVal reflect.Value
 	first := true
 	for _, key := range v.MapKeys() {
-		elem := v.MapIndex(key)
+		elem := unwrapInterface(v.MapIndex(key))
 		if !isOrderedKind(elem.Kind()) {
 			return nil, fmt.Errorf("unsupported element type: %s", elem.Kind())
 		}
@@ -440,6 +440,16 @@ func isNumericKind(k reflect.Kind) bool {
 	}
 }
 
+// unwrapInterface returns v.Elem() when v holds an interface value, otherwise v unchanged.
+// This is necessary when iterating map[string]interface{} or []interface{} via reflection:
+// the element Kind is reflect.Interface, not the underlying concrete type.
+func unwrapInterface(v reflect.Value) reflect.Value {
+	if v.Kind() == reflect.Interface {
+		return v.Elem()
+	}
+	return v
+}
+
 // isOrderedKind reports whether k supports comparison ordering.
 func isOrderedKind(k reflect.Kind) bool {
 	switch k {