feat(forum): multi-tab topic widget lazy REST load

SSR first tab; other tabs fetch /forum/frontend/widgets/topics
on switch, with shared list markup and styles.

assets/css/frontend/widget-batch5.css

@@ -718,3 +718,61 @@
 .aksrt-badge-modal__card { padding: 12px 8px 8px; }
 .aksrt-badge-modal__actions { margin-top: 12px; }
 .aksrt-author-hero__badges { margin-top: 8px; }
+
+/* Forum tab topics (batch6) */
+.aksrt-ftab__nav {
+  display: flex;
+  gap: 6px;
+  list-style: none;
+  margin: 0 0 10px;
+  padding: 0;
+  overflow-x: auto;
+}
+.aksrt-ftab__btn {
+  border: 0;
+  background: var(--surface-2, #f3f4f6);
+  border-radius: 999px;
+  padding: 5px 12px;
+  font-size: 13px;
+  cursor: pointer;
+  color: inherit;
+}
+.aksrt-ftab__btn.is-active {
+  background: var(--color-primary, #3b82f6);
+  color: #fff;
+}
+.aksrt-ftab__panel { display: none; }
+.aksrt-ftab__panel.is-active { display: block; }
+.aksrt-ftab__empty { font-size: 13px; color: var(--muted-2-color, #999); padding: 8px 0; }
+.aksrt-ftopic-list { list-style: none; margin: 0; padding: 0; }
+.aksrt-ftopic-list__item {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 8px;
+  padding: 7px 0;
+  border-bottom: 1px dashed var(--color-line, #eee);
+  font-size: 13px;
+}
+.aksrt-ftopic-list__item:last-child { border-bottom: 0; }
+.aksrt-ftopic-list__link {
+  color: inherit;
+  text-decoration: none;
+  flex: 1;
+  min-width: 0;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+.aksrt-ftopic-list__views { color: var(--muted-2-color, #999); font-size: 12px; flex-shrink: 0; }
+.aksrt-ftopic-list__meta {
+  display: flex;
+  gap: 8px;
+  font-size: 11px;
+  color: var(--muted-2-color, #999);
+  margin-top: 4px;
+}
+.aksrt-ftopic-list.is-detail .aksrt-ftopic-list__item {
+  flex-direction: column;
+  align-items: flex-start;
+}