feat: secure and document book reviews system

Added rate limiting to APIs, cleaned up docs, implemented fallback logic for reviews without text, and added comprehensive n8n guide.

package.json

@@ -116,7 +116,7 @@
     "postcss": "^8.4.49",
     "prisma": "^5.22.0",
     "tailwindcss": "^3.4.17",
-    "ts-jest": "^29.2.5",
+    "ts-jest": "^29.4.6",
     "ts-node": "^10.9.2",
     "tsx": "^4.20.5",
     "typescript": "5.9.3",