Realtime collaboration helpers.

Tiptapex collaboration runs Yjs (CRDT) documents over Phoenix Channels: the browser bundles the Yjs runtime (via the optional "tiptapex/collaboration" JS entry point) and the server relays binary sync/awareness messages between peers with Tiptapex.Collab.Channel.

Wiring it up:

1. Mount a channel using the macro on your socket:

   # lib/my_app_web/channels/user_socket.ex
   channel "doc:*", MyAppWeb.DocChannel
   
   defmodule MyAppWeb.DocChannel do
     use Tiptapex.Collab.Channel
   
     @impl true
     def authorize("doc:" <> id, _params, socket) do
       # your auth: load the record, check socket.assigns…
       {:ok, socket}
     end
   end

2. Build the JS hook with the collab plugin:

   import { makeEditorHook, TiptapexViewerHook } from "tiptapex"
   import { CollabPlugin } from "tiptapex/collaboration"
   
   const hooks = {
     TiptapexEditor: makeEditorHook({ collab: CollabPlugin }),
     TiptapexViewer: TiptapexViewerHook,
   }

3. Pass collab to the component:

   <.tiptapex_editor
     id="body"
     value={@doc}
     collab={%{topic: "doc:" <> @id, user: Tiptapex.Collab.user(%{id: user.id, name: user.name})}}
   />