feat(widgets): multi-tab posts lazy REST load

SSR first tab; other tabs fetch /widgets/tab-posts on switch
via widget-set.js (zibll tab_post depth).

assets/js/widget-set.js

@@ -17,6 +17,39 @@
       var tabs = widget.querySelectorAll('.widget-tab-posts__tab');
       var panels = widget.querySelectorAll('.widget-tab-posts__panel');
       if (!tabs.length || !panels.length) return;
+      var rest = widget.getAttribute('data-rest') || '';
+      var defaultCount = widget.getAttribute('data-count') || '5';
+
+      function loadPanel(panel, tab) {
+        if (!panel || panel.getAttribute('data-loaded') === '1' || !rest) return;
+        var orderby = tab.getAttribute('data-orderby') || 'date';
+        var cat = tab.getAttribute('data-cat') || '0';
+        var tabCount = tab.getAttribute('data-tab-count') || '0';
+        var qs = new URLSearchParams({
+          count: defaultCount,
+          orderby: orderby,
+          cat: cat,
+          tab_count: tabCount,
+        });
+        var url = rest + (rest.indexOf('?') > -1 ? '&' : '?') + qs.toString();
+        panel.classList.add('is-ajax-loading');
+        var headers = { Accept: 'application/json' };
+        if (window.aksrtData && aksrtData.restNonce) {
+          headers['X-WP-Nonce'] = aksrtData.restNonce;
+        }
+        fetch(url, { credentials: 'same-origin', headers: headers })
+          .then(function (r) { return r.json(); })
+          .then(function (j) {
+            var d = (j && j.data) || j || {};
+            var html = d.html || '';
+            panel.innerHTML = html || '<p class="widget-empty">暂无文章</p>';
+            panel.setAttribute('data-loaded', '1');
+            panel.classList.remove('is-ajax-loading');
+          })
+          .catch(function () {
+            panel.classList.remove('is-ajax-loading');
+          });
+      }
 
       tabs.forEach(function (tab) {
         tab.addEventListener('click', function () {
@@ -33,6 +66,7 @@
             panel.classList.toggle('active', active);
             if (active) {
               panel.removeAttribute('hidden');
+              loadPanel(panel, tab);
             } else {
               panel.setAttribute('hidden', '');
             }