feat: 添加隐藏CCS导入按钮的设置选项

在管理后台设置页面新增开关，允许管理员隐藏API Keys页面的"导入CCS"按钮

backend/internal/service/settings_view.go

@@ -25,13 +25,14 @@ type SystemSettings struct {
 	LinuxDoConnectClientSecretConfigured bool
 	LinuxDoConnectRedirectURL            string
 
-	SiteName     string
-	SiteLogo     string
-	SiteSubtitle string
-	APIBaseURL   string
-	ContactInfo  string
-	DocURL       string
-	HomeContent  string
+	SiteName            string
+	SiteLogo            string
+	SiteSubtitle        string
+	APIBaseURL          string
+	ContactInfo         string
+	DocURL              string
+	HomeContent         string
+	HideCcsImportButton bool
 
 	DefaultConcurrency int
 	DefaultBalance     float64
@@ -66,6 +67,7 @@ type PublicSettings struct {
 	ContactInfo         string
 	DocURL              string
 	HomeContent         string
+	HideCcsImportButton bool
 	LinuxDoOAuthEnabled bool
 	Version             string
 }