Uniswap/uniswapx-service ? reverse-engineered prompt

Build me a TypeScript service for UniswapX order handling that lets swappers submit signed orders, validates them, stores them, tracks their status, and serves them back to fillers through a simple API.

I want endpoints for posting dutch auction and limit orders, getting order feeds with filters, checking the next nonce for an address, and serving the OpenAPI docs and Swagger UI. When an order comes in, it should decode the payload, check the signature and timing rules, do the needed onchain checks, then save it in DynamoDB and start tracking it until it becomes open, filled, cancelled, expired, or errors out. If it is a priority order, it should be cosigned with an AWS KMS key.

Please make it work the way a real production service would, with tests, schema validation, and the AWS pieces wired up so it can be deployed. If you need to look up current docs online while building it, go ahead.