hive-c0re: correct stale tuwunel 1.6.x version claim in matrix admin-room doc comment

hive-c0re/src/matrix.rs

@@ -888,8 +888,16 @@ pub async fn ensure_admin_user(client: &reqwest::Client, register_token: &str) -
 /// (`#admins:<server>`). Sends `!admin users make-user-admin @<localpart>:<server>` as
 /// @hive, polls for the bot's "Done:" success response.
 ///
-/// tuwunel 1.6.x does not implement `/_synapse/admin/v2/users`; all admin
-/// operations go through the admin room.
+/// Historically justified by tuwunel 1.6.x not implementing
+/// `/_synapse/admin/v2/users` — but this repo now deploys 1.8.3, and that
+/// premise has not been re-verified against it. A binary grep of a deployed
+/// 1.8.3 found the route string present, which is evidence but not proof (a
+/// string match doesn't confirm the route is actually served to an admin
+/// token, as opposed to rejected, an error message, or a client-side
+/// constant). Whether the admin-room polling mechanism here can be replaced
+/// with a direct HTTP call is an open question tracked on the forge,
+/// pending an actual authenticated request against a running homeserver —
+/// leaving the mechanism as-is until that's answered.
 pub async fn promote_user_to_admin(
     client: &reqwest::Client,
     admin_token: &str,