feat: add agent user edit, card type permission check and balance deduction

- Backend: check AgentApplicationCardType.can_generate before allowing card recharge
- Backend: deduct agent balance and record consumption when creating user with card
- Backend: add GET /agent/users/:id and PUT /agent/users/:id for user edit
- Backend: extract checkAgentUserPermission helper, refactor handleUpdateUserStatus
- Frontend: add user edit page ([id].vue) with username/email/password
- Frontend: add edit action in user list dropdown menu
- Frontend: add route for agent user edit page
- Add i18n keys for agent user edit

frontend/src/plugins/i18n/en.json

@@ -2823,6 +2823,26 @@
         "cancel": "Cancel",
         "success": "User created successfully",
         "failed": "Failed to create user"
+      },
+      "edit": {
+        "title": "Edit User",
+        "basicInfo": "Basic Information",
+        "basicInfoDesc": "Modify user basic information",
+        "username": "Username",
+        "usernamePlaceholder": "Enter username",
+        "usernameRequired": "Username is required",
+        "email": "Email",
+        "emailPlaceholder": "Enter email (optional)",
+        "password": "Password",
+        "passwordPlaceholder": "Leave empty to keep unchanged",
+        "passwordHint": "Leave empty to keep the current password",
+        "preview": "Preview",
+        "usernameLabel": "Username",
+        "emailLabel": "Email",
+        "saveBtn": "Save Changes",
+        "cancel": "Cancel",
+        "success": "User updated successfully",
+        "failed": "Failed to load user info"
       }
     },
     "apps": {

frontend/src/plugins/i18n/zh.json

@@ -2825,6 +2825,26 @@
         "cancel": "取消",
         "success": "用户创建成功",
         "failed": "用户创建失败"
+      },
+      "edit": {
+        "title": "编辑用户",
+        "basicInfo": "基本信息",
+        "basicInfoDesc": "修改用户基本信息",
+        "username": "用户名",
+        "usernamePlaceholder": "请输入用户名",
+        "usernameRequired": "用户名不能为空",
+        "email": "邮箱",
+        "emailPlaceholder": "请输入邮箱（选填）",
+        "password": "密码",
+        "passwordPlaceholder": "留空则不修改",
+        "passwordHint": "留空则不修改密码",
+        "preview": "预览",
+        "usernameLabel": "用户名",
+        "emailLabel": "邮箱",
+        "saveBtn": "保存修改",
+        "cancel": "取消",
+        "success": "用户信息更新成功",
+        "failed": "获取用户信息失败"
       }
     },
     "apps": {