fix(ui): Phase 7 C5 — 移除假按钮 + 真实托盘图标

用户报告设置页很多按钮无反应 + 关闭后托盘看不到图标。两处问题：\n\n1. ServerCard 占位按钮无回调：\n- server-card.slint：去掉了 toggled/edit-clicked/remove-clicked 三个回调以及 enabled 切换、Edit / Remove 按钮；变成纯展示卡（状态点 + name + url + 当前标记）\n- settings-page.slint：去掉硬编码的 Home / NAS 占位，改用 active-server-name / active-server-url / active-server-enabled 三个属性（MainWindow → AppConfig 实时填充）；空时显示 '（未配置服务器）' 空态提示\n- app.slint：MainWindow 加三个属性 + 转发给 SettingsPage\n- lib.rs：startup 阶段把活跃服务器信息塞进 UI；测试连接成功/失败时更新 enabled 状态\n\n2. 托盘图标看不见：\n- tray.rs：原本 hIcon 写 null，Win10+ 上 Shell_NotifyIconW(NIM_ADD, NULL hIcon) 实际渲染为空白或很弱的小方块。改用 LoadIconW(NULL, IDI_APPLICATION) 加载 Windows 自带的应用程序图标（无需嵌入 .ico 资源，主题感知）。show_toast / Drop 的 hIcon 维持 null（让 NIM_MODIFY/NIM_DELETE 不动原有图标）。AGENTS.md §53 标记真 .ico 资源为 V2 项。

ui/app.slint

@@ -86,6 +86,13 @@ export component MainWindow inherits Window {
     in-out property <string> status-text: "未连接";
     callback test-connection-requested();
 
+    // Phase 7 C5: active-server summary forwarded into SettingsPage
+    // so the Connection section reflects the real AppConfig instead
+    // of the old hardcoded "Home / NAS" placeholders.
+    in property <string> active-server-name: "（未配置服务器）";
+    in property <string> active-server-url: "";
+    in property <bool> active-server-enabled: false;
+
     HorizontalLayout {
         // §7 Sidebar width: 220-240px.
         Rectangle {
@@ -379,6 +386,12 @@ export component MainWindow inherits Window {
                 start-with-windows: root.start-with-windows;
                 start-minimized: root.start-minimized;
                 close-to-tray: root.close-to-tray;
+                // Phase 7 C5: forward active server config so the
+                // Connection section shows the real entry instead
+                // of the hardcoded "Home / NAS" placeholders.
+                active-server-name: root.active-server-name;
+                active-server-url: root.active-server-url;
+                active-server-enabled: root.active-server-enabled;
                 appearance-changed(idx) => {
                     root.appearance-index = idx;
                     root.theme = idx == 0 ? AppearanceMode.System :