Room channel: other T5DE users' community products on their avatars

The proxy follows the client's IMQ chat subscriptions and tells the hub which chats it's in (and the room, from
chat.getOrMakeChat). For the other T5DE users the hub says are in a chat, it gives the client the community
products it has packs for, as *use and *remove lines from them, and adds them to the whole outfits they send.
It also takes community products out of the outfit the client posts to IMVU's chat participant endpoint, which
had been sending them to IMVU.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

README.md

@@ -60,8 +60,13 @@ leaves the machine.
 API): it shows a code to enter on the hub's website (`/device`, OAuth 2.0 device authorization) and saves the
 session token it gets in `%APPDATA%\T5DE\proxy\hub.json`, encrypted for the Windows user (DPAPI). From then on the
 running proxy keeps a WebSocket to the hub (`internal/hub`) with the token as a bearer token, reporting which IMVU
-account the client signed in as and the community products it wears. If the hub ends the session (signed out
-everywhere, banned), the proxy stops connecting until `signin` is run again.
+account the client signed in as, the community products it wears, and the IMVU chats it's in. If the hub ends the
+session (signed out everywhere, banned), the proxy stops connecting until `signin` is run again.
+
+The room channel (`internal/products/room.go`): the hub tells the proxy which other T5DE users are in the same chat
+and what they wear; the proxy gives the client those of their products it has packs for, as `*use`/`*remove` lines
+from them, and adds them to the whole outfits they send. It also keeps community products out of the outfit the
+client posts to IMVU's chat participant endpoint.
 
 ## Building