fix(rmeets): remove loading spinner after Jitsi iframe injection

The "Connecting to meeting..." loading div remained visible on top of
the Jitsi iframe in the minimal view. The iframe is created by the
JitsiMeetExternalAPI constructor, so remove the spinner immediately after.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

modules/rmeets/mod.ts

@@ -539,6 +539,9 @@ routes.get("/:room", (c) => {
         DISABLE_JOIN_LEAVE_NOTIFICATIONS: false,
       },
     });
+    // Remove loading spinner — iframe is already injected by the constructor
+    var loadingEl = document.querySelector(".loading");
+    if (loadingEl) loadingEl.remove();
     api.addEventListener("readyToClose", function() {
       try { window.close(); } catch(e) {}
       document.getElementById("jitsi-container").innerHTML =