Imagine you are a contractor on a gig. You don't wait until things break before you ask for access. You ask, before the job starts, what all the doors are and who has the the keys. So: "hey, Recruiter, in order to make this task a success next week and make you and me both look good I will need some stuff ready on day 1: what's your code repo system ? MFA?internal comms channel? bug system? internal knowledge base? and most importantly, if it's not you who can administer access to these things, who is the person I talk to, and can you arrange an intro on day 1?"
To not show this level of initiative, and sit around while your friend navigates the corporate machine for you, is the behavior of a new intern, not a senior developer. OP also doesnt say that they arranged a live end of Day 1 checkin with their task manager, which is another miss, since it allows for the latter to mop up any lingering issues ("oh yeah I forgot you need access to X, let me sort that out") and for the former to remind them that this is an odd task ("it was interesting that you asked an Elixir dev to work on a browser extension")
As far as being asked to work in TypeScript not Elixir, thats certainly odd, but could have been deliberate and not necessarily foolish. Maybe they wanted to see how intellectually adaptable OP was. Maybe they wanted to see if you would speak up and handle potential conflict. Or maybe they had a mixup between two candidates. We'll never know because OP sent a wall of text which surely would not have helped defuse the situation.