fix(config): expose forward compact mode switch in settings (#241)

## Summary
- Add `forward_compact_mode` to the `/config` settings item list so the
compact-mode switch is visible in the main settings page.
- Include `forward_compact_mode` in initial config cache keys to keep
switch state consistent on load.

## Verification
- `npm run build` (vite-frontend)

vite-frontend/src/pages/config.tsx

@@ -117,6 +117,12 @@ const CONFIG_ITEMS: ConfigItem[] = [
     description: "用于浏览器标签页图标，上传后会自动转换为 PNG 并持久化保存",
     type: "input",
   },
+  {
+    key: "forward_compact_mode",
+    label: "转发页面精简模式",
+    description: "开启后，转发页面列表使用 2.1.6-alpha8 样式（全局配置）",
+    type: "switch",
+  },
   {
     key: "captcha_enabled",
     label: "启用验证码",
@@ -167,6 +173,7 @@ const getInitialConfigs = (): Record<string, string> => {
     "captcha_enabled",
     "cloudflare_site_key",
     "cloudflare_secret_key",
+    "forward_compact_mode",
     "ip",
     "panel_domain",
     "app_logo",