Add errorx.AnyOf for sentinel error checks

Centralize errors.Is OR chains in access review campaign resolvers
and expose CampaignStatusErrors for the four non-draft status
sentinels.

Signed-off-by: Cursor Agent <cursoragent@cursor.com>

Co-authored-by: Bryan FRIMIN <bryan@frimin.fr>

pkg/accessreview/errors.go

@@ -34,6 +34,14 @@ var (
 	ErrCampaignCancelled      = errors.New("campaign is cancelled")
 )
 
+// CampaignStatusErrors are client-facing invalid-state errors for non-draft campaigns.
+var CampaignStatusErrors = []error{
+	ErrCampaignInProgress,
+	ErrCampaignPendingActions,
+	ErrCampaignCompleted,
+	ErrCampaignCancelled,
+}
+
 func CampaignStatusError(status coredata.AccessReviewCampaignStatus) error {
 	switch status {
 	case coredata.AccessReviewCampaignStatusInProgress: