Send unresolved-type hint to stderr, not stdout

On a failed create or update --type, the available-types list was
rendered through the active renderer to stdout, so --format json
emitted a types array instead of nothing. Add printer.AvailableTypes,
which lists names on stderr, and use it on both not-found paths so
stdout carries only the command result.

Author: myabc

components/printer/types.go

@@ -1,7 +1,20 @@
 package printer
 
-import "github.com/opf/openproject-cli/models"
+import (
+	"fmt"
+
+	"github.com/opf/openproject-cli/models"
+)
 
 func Types(types []*models.Type) {
 	activeRenderer.Types(types)
 }
+
+// AvailableTypes lists type names on standard error as a guidance hint, so it
+// never pollutes machine-readable output (e.g. JSON) on a failed command.
+func AvailableTypes(types []*models.Type) {
+	Info("Available types:")
+	for _, t := range types {
+		Info(fmt.Sprintf("  - %s", t.Name))
+	}
+}

components/resources/work_packages/create.go

@@ -51,7 +51,7 @@ func typeCreate(projectId string, workPackage *dtos.WorkPackageDto, input string
 			printer.Cyan(input),
 			printer.Red(projectId),
 		))
-		printer.Types(types.Convert())
+		printer.AvailableTypes(types.Convert())
 		return openerrors.ErrHandled
 	}
 

components/resources/work_packages/create_test.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"strings"
 	"testing"
 
 	openerrors "github.com/opf/openproject-cli/components/errors"
@@ -49,3 +50,42 @@ func TestCreateRejectsInvalidTypeBeforePosting(t *testing.T) {
 		t.Errorf("POST count = %d, want 0", postCount)
 	}
 }
+
+// On an unresolved --type, the "available types" hint is guidance and must go
+// to stderr, never to stdout, so --format json output stays clean.
+func TestCreateInvalidTypeHintGoesToStderr(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(response http.ResponseWriter, request *http.Request) {
+		response.Header().Set("Content-Type", "application/json")
+		switch {
+		case request.Method == http.MethodGet && request.URL.Path == "/api/v3/projects/1":
+			_, _ = response.Write([]byte(`{"_links":{"types":{"href":"/api/v3/projects/1/types"}}}`))
+		case request.Method == http.MethodGet && request.URL.Path == "/api/v3/projects/1/types":
+			_, _ = response.Write([]byte(`{"_embedded":{"elements":[{"id":7,"name":"Task"}]}}`))
+		default:
+			http.Error(response, "unexpected request", http.StatusNotFound)
+		}
+	}))
+	t.Cleanup(server.Close)
+
+	host, err := url.Parse(server.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	requests.Init(host, "", false)
+	testingPrinter := &printer.TestingPrinter{}
+	printer.Init(testingPrinter)
+
+	_, err = work_packages.Create("1", map[work_packages.CreateOption]string{
+		work_packages.CreateSubject: "Subject",
+		work_packages.CreateType:    "Missing",
+	})
+	if !errors.Is(err, openerrors.ErrHandled) {
+		t.Fatalf("Create error = %v, want ErrHandled", err)
+	}
+	if testingPrinter.Result != "" {
+		t.Errorf("stdout = %q, want empty on failed create", testingPrinter.Result)
+	}
+	if !strings.Contains(testingPrinter.ErrResult, "Task") {
+		t.Errorf("stderr = %q, want it to list available type %q", testingPrinter.ErrResult, "Task")
+	}
+}

components/resources/work_packages/update.go

@@ -184,7 +184,7 @@ func typePatch(patch, workPackage *dtos.WorkPackageDto, input string) (string, e
 			printer.Red(fmt.Sprintf("#%d", parser.IdFromLink(workPackage.Links.Project.Href))),
 		))
 
-		printer.Types(types.Convert())
+		printer.AvailableTypes(types.Convert())
 
 		return "", openerrors.ErrHandled
 	}