Formalize CreateFlowState + validate draft/publish API payloads

package-lock.json

@@ -20,7 +20,8 @@
         "next-intl": "^3.26.5",
         "nodemailer": "^6.9.16",
         "react": "^19.0.0",
-        "react-dom": "^19.0.0"
+        "react-dom": "^19.0.0",
+        "zod": "^3.25.76"
       },
       "devDependencies": {
         "@axe-core/playwright": "^4.10.2",
@@ -23129,7 +23130,6 @@
       "version": "3.25.76",
       "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
       "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
-      "dev": true,
       "license": "MIT",
       "funding": {
         "url": "https://github.com/sponsors/colinhacks"