fix(ws): replace unreachable_unchecked with safe fallback for TypingStart/TypingStop

TypingStart/TypingStop actions are intercepted in ws_universal.rs so
this match arm is never reached, but we need a safe fallback instead
of std::hint::unreachable_unchecked().

libs/api/room/ws_handler.rs

@@ -728,6 +728,9 @@ impl WsRequestHandler {
             WsAction::UnsubscribeRoom => Ok(WsResponseData::bool(true)),
             WsAction::SubscribeProject => Ok(WsResponseData::subscribed(None, None)),
             WsAction::UnsubscribeProject => Ok(WsResponseData::bool(true)),
+            // TypingStart/TypingStop are handled directly in ws_universal.rs
+            // (interception point sends response there, so this arm is never reached)
+            WsAction::TypingStart | WsAction::TypingStop => Ok(WsResponseData::bool(true)),
         }
     }
 }