assetsrepository is open source. You are free to use it and free to create your version (fork). But we choose to ask for a contribution for requests to include/change the information in the Trust Wallet product. See also Why question.
merge-fee-bot, a GitHub app by us. Currently, payment is checked only when there is some action on the PR, such as a comment. So after your transfer, create a comment about it. The payment should be detected within seconds. (Technical background: being notified when the payment happens is not a problem, but interacting with a PR when there is no action on it is difficult for the GitHub app.)
merge-fee-botdetects payment, it automatically places an Accept review on the PR. This is a precondition for merge. But merging is currently not automatic, it is done by the maintainers.