do not wipe actions

src/Runner.Worker/Dap/StepCommands/StepCommandHandler.cs

@@ -542,9 +542,14 @@ EXAMPLES:
                     Trace.Info($"Preparing action '{command.Action}' for download...");
                     
                     // PrepareActionsAsync downloads the action and returns info about pre/post steps
+                    // Pass actionStep.Id as rootStepId to avoid wiping the _actions directory.
+                    // When rootStepId is default(Guid), PrepareActionsAsync assumes it's the start
+                    // of a job and deletes all previously downloaded actions - which would break
+                    // post-steps from actions that were already running.
                     var prepareResult = await actionManager.PrepareActionsAsync(
                         jobContext,
-                        new[] { actionStep }
+                        new[] { actionStep },
+                        actionStep.Id
                     );
 
                     // Check if this action has a pre-step