feat!: rework the public API to json/v2-style variadic options

Assisted-by: GLM 5.3 Flash

interpres_test.go

@@ -317,7 +317,7 @@ func TestDisallowUnknownFields(t *testing.T) {
 	}
 
 	var strict C
-	err := NewDecoder().DisallowUnknownFields().Decode(data, &strict)
+	err := Unmarshal(data, &strict, RejectUnknownFields(true))
 	if err == nil {
 		t.Fatal("expected error for unknown field, got nil")
 	}
@@ -333,7 +333,7 @@ func TestDisallowUnknownFieldsReportsSmallestKey(t *testing.T) {
 	data := []byte("known = \"x\"\nzeta = 1\nalpha = 2\nmu = 3\n")
 	for range 20 {
 		var c C
-		err := NewDecoder().DisallowUnknownFields().Decode(data, &c)
+		err := Unmarshal(data, &c, RejectUnknownFields(true))
 		if err == nil {
 			t.Fatal("expected error for unknown fields")
 		}