fix: 订阅模式登录验证、永久会员类型区分、动态代码HTTP返回值修复、侧边栏滚动位置保持

- 修复订阅模式登录时错误检查余额的问题
- 区分无限余额和永久订阅两种永久会员类型
- 修复动态代码HTTP请求返回值在JS中无法正确访问的问题
- 添加侧边栏滚动位置保持功能
- 移除developer角色相关代码，统一使用admin
- 添加缺失的i18n翻译key

backend/internal/database/database.go

@@ -331,13 +331,26 @@ func initData() {
 	}
 
 	// 迁移：将 developer 角色统一为 admin
-	var developerCount int64
-	DB.Model(&model.User{}).Where("role = ?", "developer").Count(&developerCount)
-	if developerCount > 0 {
-		log.Printf("Migrating %d developer users to admin role...", developerCount)
+	var devRoleCount int64
+	DB.Model(&model.User{}).Where("role = ?", "developer").Count(&devRoleCount)
+	if devRoleCount > 0 {
+		log.Printf("Migrating %d developer users to admin role...", devRoleCount)
 		DB.Model(&model.User{}).Where("role = ?", "developer").Update("role", "admin")
 	}
 
+	// 迁移：将 developer_id 列名改为 admin_id
+	if DB.Migrator().HasColumn(&model.AgentApplication{}, "developer_id") {
+		log.Println("Migrating agent_applications.developer_id to admin_id...")
+		DB.Exec("ALTER TABLE agent_applications RENAME COLUMN developer_id TO admin_id")
+	}
+	if DB.Migrator().HasColumn(&model.AgentApplicationRequest{}, "developer_id") {
+		log.Println("Migrating agent_application_requests.developer_id to admin_id...")
+		DB.Exec("ALTER TABLE agent_application_requests RENAME COLUMN developer_id TO admin_id")
+	}
+
+	// 迁移：将 write_permission 默认值从 developer 改为 admin
+	DB.Exec("UPDATE cloud_variables SET write_permission = 'admin' WHERE write_permission = 'developer'")
+
 	// 清理没有关联应用的云端常量和变量
 	var orphanConstants int64
 	DB.Model(&model.CloudConstant{}).Where("app_id IS NULL").Count(&orphanConstants)