feat(account): 优化批量更新实现，使用统一 SQL 合并 JSONB 字段

- 新增 BulkUpdate 仓储方法，使用单条 SQL 更新所有账户
- credentials/extra 使用 COALESCE(...) || ? 合并，只更新传入的 key
- name/proxy_id/concurrency/priority/status 只在提供时更新
- 分组绑定仍逐账号处理（需要独立操作）
- 前端优化：Base URL 留空则不修改，按勾选字段更新
- 完善 i18n 文案：说明留空不修改、批量更新行为

backend/internal/service/admin_service.go

@@ -45,6 +45,7 @@ type AdminService interface {
 	RefreshAccountCredentials(ctx context.Context, id int64) (*model.Account, error)
 	ClearAccountError(ctx context.Context, id int64) (*model.Account, error)
 	SetAccountSchedulable(ctx context.Context, id int64, schedulable bool) (*model.Account, error)
+	BulkUpdateAccounts(ctx context.Context, input *BulkUpdateAccountsInput) (*BulkUpdateAccountsResult, error)
 
 	// Proxy management
 	ListProxies(ctx context.Context, page, pageSize int, protocol, status, search string) ([]model.Proxy, int64, error)
@@ -140,6 +141,33 @@ type UpdateAccountInput struct {
 	GroupIDs    *[]int64
 }
 
+// BulkUpdateAccountsInput describes the payload for bulk updating accounts.
+type BulkUpdateAccountsInput struct {
+	AccountIDs  []int64
+	Name        string
+	ProxyID     *int64
+	Concurrency *int
+	Priority    *int
+	Status      string
+	GroupIDs    *[]int64
+	Credentials map[string]any
+	Extra       map[string]any
+}
+
+// BulkUpdateAccountResult captures the result for a single account update.
+type BulkUpdateAccountResult struct {
+	AccountID int64  `json:"account_id"`
+	Success   bool   `json:"success"`
+	Error     string `json:"error,omitempty"`
+}
+
+// BulkUpdateAccountsResult is the aggregated response for bulk updates.
+type BulkUpdateAccountsResult struct {
+	Success int                       `json:"success"`
+	Failed  int                       `json:"failed"`
+	Results []BulkUpdateAccountResult `json:"results"`
+}
+
 type CreateProxyInput struct {
 	Name     string
 	Protocol string
@@ -694,6 +722,65 @@ func (s *adminServiceImpl) UpdateAccount(ctx context.Context, id int64, input *U
 	return account, nil
 }
 
+// BulkUpdateAccounts updates multiple accounts in one request.
+// It merges credentials/extra keys instead of overwriting the whole object.
+func (s *adminServiceImpl) BulkUpdateAccounts(ctx context.Context, input *BulkUpdateAccountsInput) (*BulkUpdateAccountsResult, error) {
+	result := &BulkUpdateAccountsResult{
+		Results: make([]BulkUpdateAccountResult, 0, len(input.AccountIDs)),
+	}
+
+	if len(input.AccountIDs) == 0 {
+		return result, nil
+	}
+
+	// Prepare bulk updates for columns and JSONB fields.
+	repoUpdates := ports.AccountBulkUpdate{
+		Credentials: input.Credentials,
+		Extra:       input.Extra,
+	}
+	if input.Name != "" {
+		repoUpdates.Name = &input.Name
+	}
+	if input.ProxyID != nil {
+		repoUpdates.ProxyID = input.ProxyID
+	}
+	if input.Concurrency != nil {
+		repoUpdates.Concurrency = input.Concurrency
+	}
+	if input.Priority != nil {
+		repoUpdates.Priority = input.Priority
+	}
+	if input.Status != "" {
+		repoUpdates.Status = &input.Status
+	}
+
+	// Run bulk update for column/jsonb fields first.
+	if _, err := s.accountRepo.BulkUpdate(ctx, input.AccountIDs, repoUpdates); err != nil {
+		return nil, err
+	}
+
+	// Handle group bindings per account (requires individual operations).
+	for _, accountID := range input.AccountIDs {
+		entry := BulkUpdateAccountResult{AccountID: accountID}
+
+		if input.GroupIDs != nil {
+			if err := s.accountRepo.BindGroups(ctx, accountID, *input.GroupIDs); err != nil {
+				entry.Success = false
+				entry.Error = err.Error()
+				result.Failed++
+				result.Results = append(result.Results, entry)
+				continue
+			}
+		}
+
+		entry.Success = true
+		result.Success++
+		result.Results = append(result.Results, entry)
+	}
+
+	return result, nil
+}
+
 func (s *adminServiceImpl) DeleteAccount(ctx context.Context, id int64) error {
 	return s.accountRepo.Delete(ctx, id)
 }