Fix: harden bootstrap worker flow

Backend/internal/worker/runner.go

@@ -57,7 +57,13 @@ func (runner *Runner) Run(ctx context.Context) error {
 				return nil
 			}
 
-			return err
+			runner.logger.Error("worker claim failed", "error", err)
+
+			if err := waitForNextPoll(ctx, runner.pollInterval); err != nil {
+				return nil
+			}
+
+			continue
 		}
 
 		if job == nil {