fix(network): do not re-pin a lite server while a connect is in progress

Pinning a lite server while a connection to it was already being
established tore the in-flight connect down and restarted it, slowing
the very connection the user was waiting on.

- Pinning is now skipped while a connect is already underway, so the
  existing attempt is left to finish.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/ui/windows/network_tab.cpp

@@ -78,6 +78,8 @@ void RenderLiteNetworkTab(App* app)
         // retries the pinned one.
         auto* lite = app->liteWallet();
         if (!randomMode && url == sticky && lite && lite->walletOpen() && lite->connectedServerUrl() == url) return;
+        // A connect is already underway: re-pinning would tear it down and restart it.
+        if (lite && lite->openInProgress()) return;
         st->setLiteServerSelectionMode(LiteMode::Sticky);
         st->setLiteStickyServerUrl(url);
         applyAndRebuild();