fixes #14881

Our handlers for streaming logs don't read from the websocket. We don't allow the client to send us any data, but the websocket library we use requires reading from the websocket to properly handle pings and closing. Not doing so can [can cause the websocket to hang on write](coder/websocket#405), leaking go routines which were noticed in #14881.

This fixes the issue, and in process refactors our log streaming to a encoder/decoder package which provides generic types for sending JSON over websocket.

I'd also like for us to upgrade to the latest https://github.com/coder/websocket but we should also upgrade our tailscale fork before doing so to avoid including two copies of the websocket library.

(cherry picked from commit 148a5a3)

(cherry picked from commit a9195bf)

Fixes: #14124
(cherry picked from commit 1736309)

Fixes a bug where a file produced by `generateVersionFiles` (as used
when uploading a web UI edited template) produced a file where the
`type` field was unset.
This meant the change in #15410 used the unset type value as the content
header when uploading, causing it to always fail.

(cherry picked from commit d2e4969)

)

![image](https://github.com/user-attachments/assets/15ae6dc4-84a3-4c20-b603-ed38cc14a250)
Despite being encoded the same, the API was previously rejecting zip
files with this MIME type.

(cherry picked from commit f7cbf5d)