feat: add date-fns library for improved date handling and validation

app/gateway-api/package.json

@@ -21,6 +21,7 @@
         "@sammo-ts/common": "workspace:*",
         "@sammo-ts/infra": "workspace:*",
         "@trpc/server": "^11.4.4",
+        "date-fns": "^4.1.0",
         "fastify": "^5.3.3",
         "redis": "^5.10.0",
         "zod": "^4.2.1"