Build decision flow editor and runtime integration

server/api/decision-flows/[slug]/runtime.get.ts

@@ -0,0 +1,12 @@
+import { createError } from 'h3'
+import { buildRuntimeDecisionTree } from '../../../services/decisionFlowService'
+
+export default defineEventHandler(async (event) => {
+  const slugParam = event.context.params?.slug
+  if (typeof slugParam !== 'string' || !slugParam.trim()) {
+    throw createError({ statusCode: 400, statusMessage: 'Missing flow identifier' })
+  }
+
+  const tree = await buildRuntimeDecisionTree(slugParam.trim())
+  return tree
+})