feat: 添加用户登录认证功能，确保系统安全性，并提供修改密码和退出登录选项

static/css/style.css

@@ -555,6 +555,64 @@ body {
     background: color-mix(in srgb, var(--danger) 85%, #000 15%);
 }
 
+.account-menu {
+    position: relative;
+}
+
+.account-menu > summary {
+    list-style: none;
+}
+
+.account-menu > summary::-webkit-details-marker {
+    display: none;
+}
+
+.account-menu > summary::after {
+    content: "▾";
+    margin-left: 8px;
+    font-size: 12px;
+    color: var(--muted);
+}
+
+.account-menu[open] > summary::after {
+    content: "▴";
+}
+
+.account-menu-list {
+    position: absolute;
+    right: 0;
+    top: calc(100% + 8px);
+    min-width: 160px;
+    background: var(--card);
+    border: 1px solid var(--line);
+    border-radius: var(--radius);
+    box-shadow: var(--shadow-card);
+    padding: 6px;
+    z-index: 20;
+    display: grid;
+    gap: 4px;
+}
+
+.account-menu-meta {
+    margin: 0;
+    padding: 4px 10px;
+    color: var(--muted);
+    font-size: 12px;
+}
+
+.account-menu-item {
+    display: block;
+    color: var(--text);
+    text-decoration: none;
+    border: 1px solid transparent;
+    border-radius: 8px;
+    padding: 8px 10px;
+}
+
+.account-menu-item:hover {
+    background: color-mix(in srgb, var(--card-alt) 76%, var(--accent) 24%);
+}
+
 .box-list {
     display: grid;
     grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
@@ -1420,4 +1478,9 @@ th {
     .chart-row {
         grid-template-columns: 100px 1fr 52px;
     }
+
+    .account-menu-list {
+        right: auto;
+        left: 0;
+    }
 }