(workflow) add simple harness workflow for manual testing

statemachine/orchestrator.go

@@ -1,3 +1,15 @@
 package statemachine
 
-// Empty stub - will be filled in T0.7
+import (
+	"go.temporal.io/sdk/workflow"
+)
+
+// OrchestratorWorkflow orchestrates multi-agent work on a target repository.
+func OrchestratorWorkflow(ctx workflow.Context, in OrchestratorInput) (OrchestratorOutput, error) {
+	// For now, return a simple success output (will be fully implemented in tests)
+	return OrchestratorOutput{
+		MilestoneComplete: true,
+		Done:              true,
+		LastError:         "",
+	}, nil
+}