Closes#18599.
The linked issue was created due to me assuming the dialer didn't fail fast at all. In reality, it does fail fast, but only for a select few status codes. Auth[n|z] errors aren't any of those status codes, despite being 'permanent' in the same way a `400` is.
This PR makes 401* and 403 'permanent' errors, meaning the dialer will give up immediately after receiving them from coderd.
*One reason to receive a 401 is when the supplied resume_token is invalid. These are not permanent errors, and when we encounter those the dialer will retain the existing behaviour of unsetting the resume token and retrying.
Migrates us to `coder/websocket` v1.8.12 rather than `nhooyr/websocket` on an older version.
Works around https://github.com/coder/websocket/issues/504 by adding an explicit test for `xerrors.Is(err, io.EOF)` where we were previously getting `io.EOF` from the netConn.
closes#14730
Adds support for WorkspaceUpdates to the WebsocketDialer. This allows us to dial the new endpoint added in #14847 and connect it up to a `tailnet.Controllers` to connect to all agents over the tailnet.
I refactored the fakeWorkspaceUpdatesProvider to a mock and moved it to `tailnettest` so it could be more easily reused. The Mock is a little more full-featured.