fix: make workflow mutator property lookup case-insensitive; fix REST visitor test

SetProperty and SetActivityProperty now normalize the prop argument to
lowercase so callers using legacy uppercase strings ("PAGE", "OVERVIEW_PAGE",
etc.) continue to work. Update visitor_rest_test.go to expect lowercase
HTTP method from the REST visitor ("get" not "GET").

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ako

mdl/backend/mpr/workflow_mutator.go

@@ -55,7 +55,7 @@ func (b *MprBackend) openWorkflowForMutation(unitID model.ID) (backend.WorkflowM
 // ---------------------------------------------------------------------------
 
 func (m *mprWorkflowMutator) SetProperty(prop string, value string) error {
-	switch prop {
+	switch strings.ToLower(prop) {
 	case "display":
 		wfName := dGetDoc(m.rawData, "WorkflowName")
 		if wfName == nil {
@@ -158,7 +158,7 @@ func (m *mprWorkflowMutator) SetActivityProperty(activityRef string, atPos int,
 		return err
 	}
 
-	switch prop {
+	switch strings.ToLower(prop) {
 	case "page":
 		taskPage := dGetDoc(actDoc, "TaskPage")
 		if taskPage != nil {

mdl/visitor/visitor_rest_test.go

@@ -45,7 +45,7 @@ func TestCreateRestClient_Basic(t *testing.T) {
 	if op.Name != "GetPets" {
 		t.Errorf("Got Name %q", op.Name)
 	}
-	if op.Method != "GET" {
+	if op.Method != "get" {
 		t.Errorf("Got Method %q", op.Method)
 	}
 }