Speed up top nav with turbo routing and external base CSS.

Remove view-transition lag, swap main content without full reload, prefetch pages, and tear down SSE timers on leave.

Co-authored-by: Cursor <cursoragent@cursor.com>

static/js/plans.js

@@ -39,11 +39,20 @@
             .catch(function () { /* ignore */ });
     }
 
+    function stopPolling() {
+        if (timer) {
+            clearInterval(timer);
+            timer = null;
+        }
+    }
+
     function startPolling() {
-        if (timer) clearInterval(timer);
+        stopPolling();
         pollPrices();
         timer = setInterval(pollPrices, 1000);
     }
 
-    document.addEventListener('DOMContentLoaded', startPolling);
+    if (window.qihuoOnPageLoad) window.qihuoOnPageLoad(startPolling);
+    else document.addEventListener('DOMContentLoaded', startPolling);
+    if (window.qihuoOnPageLeave) window.qihuoOnPageLeave(stopPolling);
 })();