refactor: migrate wechat to user attributes and enhance users list

Migrate the hardcoded wechat field to the new extensible user
attributes system and improve the users management UI.

Migration:
- Add migration 019 to move wechat data to user_attribute_values
- Remove wechat field from User entity, DTOs, and API contracts
- Clean up wechat-related code from backend and frontend

UsersView enhancements:
- Add text labels to action buttons (Filter Settings, Column Settings,
  Attributes Config) for better UX
- Change status column to show colored dot + Chinese text instead of
  English text
- Add dynamic attribute columns support with batch loading
- Add column visibility settings with localStorage persistence
- Add filter settings modal for search and filter preferences
- Update i18n translations

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/internal/service/admin_service.go

@@ -13,7 +13,7 @@ import (
 // AdminService interface defines admin management operations
 type AdminService interface {
 	// User management
-	ListUsers(ctx context.Context, page, pageSize int, status, role, search string) ([]User, int64, error)
+	ListUsers(ctx context.Context, page, pageSize int, filters UserListFilters) ([]User, int64, error)
 	GetUser(ctx context.Context, id int64) (*User, error)
 	CreateUser(ctx context.Context, input *CreateUserInput) (*User, error)
 	UpdateUser(ctx context.Context, id int64, input *UpdateUserInput) (*User, error)
@@ -69,7 +69,6 @@ type CreateUserInput struct {
 	Email         string
 	Password      string
 	Username      string
-	Wechat        string
 	Notes         string
 	Balance       float64
 	Concurrency   int
@@ -80,7 +79,6 @@ type UpdateUserInput struct {
 	Email         string
 	Password      string
 	Username      *string
-	Wechat        *string
 	Notes         *string
 	Balance       *float64 // 使用指针区分"未提供"和"设置为0"
 	Concurrency   *int     // 使用指针区分"未提供"和"设置为0"
@@ -251,9 +249,9 @@ func NewAdminService(
 }
 
 // User management implementations
-func (s *adminServiceImpl) ListUsers(ctx context.Context, page, pageSize int, status, role, search string) ([]User, int64, error) {
+func (s *adminServiceImpl) ListUsers(ctx context.Context, page, pageSize int, filters UserListFilters) ([]User, int64, error) {
 	params := pagination.PaginationParams{Page: page, PageSize: pageSize}
-	users, result, err := s.userRepo.ListWithFilters(ctx, params, status, role, search)
+	users, result, err := s.userRepo.ListWithFilters(ctx, params, filters)
 	if err != nil {
 		return nil, 0, err
 	}
@@ -268,7 +266,6 @@ func (s *adminServiceImpl) CreateUser(ctx context.Context, input *CreateUserInpu
 	user := &User{
 		Email:         input.Email,
 		Username:      input.Username,
-		Wechat:        input.Wechat,
 		Notes:         input.Notes,
 		Role:          RoleUser, // Always create as regular user, never admin
 		Balance:       input.Balance,
@@ -310,9 +307,6 @@ func (s *adminServiceImpl) UpdateUser(ctx context.Context, id int64, input *Upda
 	if input.Username != nil {
 		user.Username = *input.Username
 	}
-	if input.Wechat != nil {
-		user.Wechat = *input.Wechat
-	}
 	if input.Notes != nil {
 		user.Notes = *input.Notes
 	}