style(dnfs): 美化卡片发帖用户显示为头像+昵称胶囊

- dnfs.js: owner 纯文本改为首字符圆形头像 + 昵称，空值兜底匿名
- theme.css: 新增 Owner Chip 样式段，复用主题变量自动适配深色模式

static/public/css/theme.css

@@ -224,6 +224,38 @@ input[type="button"]:disabled {
 .recommend-list .card h3 { transition: color 0.15s; }
 .recommend-list .card p { font-size: 0.9rem; line-height: 1.6; color: var(--fg-secondary); }
 
+/* ===== Owner Chip (dnfs 发帖用户) ===== */
+.card-owner {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.4rem;
+    margin-top: 0.2rem;
+}
+.owner-avatar {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    width: 22px;
+    height: 22px;
+    border-radius: 50%;
+    background: var(--accent-soft);
+    color: var(--accent-dark);
+    border: 1px solid var(--accent);
+    font-size: 0.7rem;
+    font-weight: 700;
+    flex-shrink: 0;
+    user-select: none;
+}
+.owner-name {
+    font-size: 0.8rem;
+    font-weight: 600;
+    color: var(--fg-secondary);
+    max-width: 200px;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+}
+
 /* ===== Minimap (dnfs) ===== */
 .minimap {
     position: fixed;