feat: 文章标签展示、搜索框清除按钮

- 文章详情页和文章卡片展示标签
- 搜索框右侧添加 × 清除按钮
- 标签点击跳转文章列表页自动搜索
- 修复 hasAnyFilter 未包含 tags 的 bug

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/css/main.css

@@ -164,6 +164,25 @@ body {
   opacity: 0.9;
 }
 
+/* 标签 */
+.tag-pill {
+  display: inline-flex;
+  align-items: center;
+  padding: 0.125rem 0.625rem;
+  border-radius: 9999px;
+  font-size: 0.75rem;
+  font-weight: 500;
+  background-color: var(--color-bg-hover);
+  color: var(--color-text-secondary);
+  transition: background-color 0.15s ease, color 0.15s ease;
+  text-decoration: none;
+}
+
+.tag-pill:hover {
+  background-color: var(--color-primary);
+  color: white;
+}
+
 /* 滚动条 */
 ::-webkit-scrollbar {
   width: 6px;