fix(web): 文章头恢复居中排版，内容区补 4px 右留白

- 文章头：align-items center + text-align center + gap 12 + padding 4px 0（旧版规则）
- 文章元信息：改回 .article-meta 12px 行，圆点 3px、左右 8px（原来用 Space + 13px 文本）
- 内容区补 padding-right 4px（旧版 scroll 容器的留白），整体宽度与原版一致

stash-web/src/components/content/ArticleDetailView.tsx

@@ -39,20 +39,16 @@ export function ArticleDetailView({ article, categoryTitle, onBack }: ArticleDet
           </button>
         </Title>
 
-        <Space gap="sm" wrap>
+        <div className="article-meta">
           {meta.map((text, index) => (
-            <Space gap="sm" key={text}>
-              {index > 0 && (
-                <span className="article-meta-dot" aria-hidden="true">
-                  ·
-                </span>
-              )}
-              <Text size="sm" tone="muted">
+            <span className="article-meta-item" key={text}>
+              {index > 0 && <i className="article-meta-dot" aria-hidden="true" />}
+              <Text size="xs" tone="muted">
                 {text}
               </Text>
-            </Space>
+            </span>
           ))}
-        </Space>
+        </div>
       </header>
 
       <Card padding="none" className="article-body-card">