Clear diagnostics UI immediately, then refresh

pikit-web/assets/diaglog.js

@@ -159,6 +159,9 @@ export async function initDiagUI({ elements, toast }) {
       await clearDiagLog();
       uiBuffer.length = 0;
       appendUi("info", "Cleared diagnostics");
+      // Immediately reflect empty log in UI, then refresh from server
+      if (logBox) logBox.textContent = "";
+      render([]);
       await refresh();
     } catch (e) {
       toast?.(e.error || "Failed to clear log", "error");