feat: explain refusals to delete or rerun an unfinished run

Gitea refuses to delete or rerun a run that has not finished with "this
workflow run is not done". Report "run 37 has not finished; cancel it first:
tea run cancel 37", and cover the next steps added to refusals in tests.

Signed-off-by: bircni <bircni@icloud.com>

internal/services/errors.go

@@ -58,6 +58,7 @@ const (
 	ReasonNoChanges = "no changes"        // the head branch has no commits the base lacks
 	ReasonDisabled  = "disabled"          // the workflow is disabled
 	ReasonCompleted = "completed"         // the run already finished
+	ReasonNotDone   = "not done"          // the run has not finished yet
 	ReasonKeyInUse  = "key in use"        // the SSH key is registered already
 	ReasonOwnsRepos = "owns repositories" // the user still owns repositories
 )
@@ -98,6 +99,8 @@ func (e *ConflictError) Error() string {
 		text = cmp.Or(subject, "the workflow") + " is disabled"
 	case ReasonCompleted:
 		text = cmp.Or(subject, "the run") + " is already completed"
+	case ReasonNotDone:
+		text = cmp.Or(subject, "the run") + " has not finished"
 	case ReasonKeyInUse:
 		text = "this SSH key is already registered"
 	case ReasonOwnsRepos:
@@ -145,6 +148,7 @@ var refusals = []struct {
 	{ReasonNoChanges, nil, []string{"no changes between the head and the base"}},
 	{ReasonDisabled, nil, []string{"workflow is disabled"}},
 	{ReasonCompleted, nil, []string{"already completed"}},
+	{ReasonNotDone, []int{http.StatusBadRequest}, []string{"not done"}},
 	{ReasonKeyInUse, nil, []string{"key content has been used"}},
 	{ReasonOwnsRepos, nil, []string{"ownership of repositories"}},
 	{ReasonExists, []int{http.StatusBadRequest, http.StatusConflict, http.StatusUnprocessableEntity}, []string{"already exist", "release is has no tag"}},