PR C: wire real NotaryRegistry on Chain 138 (arch step 4) (#7)

orchestrator/src/api/plans.ts

@@ -4,6 +4,7 @@ import { createHash } from "crypto";
 import { validatePlan, checkStepDependencies } from "../services/planValidation";
 import { storePlan, getPlanById, updatePlanSignature, listPlans } from "../db/plans";
 import { asyncHandler, AppError, ErrorType } from "../services/errorHandler";
+import { getTransactionState, getTransitionHistory } from "../services/stateMachine";
 import type { Plan, PlanStep } from "../types/plan";
 
 /**
@@ -194,3 +195,28 @@ export const validatePlanEndpoint = asyncHandler(async (req: Request, res: Respo
   });
 });
 
+/**
+ * GET /api/plans/:planId/state
+ * Return the current workflow state + full state-transition history.
+ * Arch note §8 + §14 (audit chain).
+ */
+export const getPlanState = asyncHandler(async (req: Request, res: Response) => {
+  const { planId } = req.params;
+  const plan = await getPlanById(planId);
+  if (!plan) {
+    throw new AppError(ErrorType.NOT_FOUND_ERROR, 404, "Plan not found");
+  }
+
+  const [state, history] = await Promise.all([
+    getTransactionState(planId),
+    getTransitionHistory(planId),
+  ]);
+
+  res.json({
+    plan_id: planId,
+    transaction_state: state,
+    legacy_status: plan.status,
+    transitions: history,
+  });
+});
+