提交2: 发布群核心功能实现

- 实现 EnsureListingConversation: 发布时建发布群,发欢迎语+二维码
- 实现 AddRenterToListingConversation: 付款后拉租客进群
- 实现 RemoveRenterFromListingConversation: 订单终态移出租客
- 实现消息可见性过滤: 租客只能看到 joined_at 之后的消息
- listing 模块注入 ListingChatCreator 接口,发布时建群
- ListingDTO 新增 listing_group_conversation_id 字段
- 付款流程改为拉租客进发布群(替代建订单群)
- 订单完成和取消时自动移出租客
- 创建 chat 适配器实现接口解耦

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/internal/modules/listing/dto.go

@@ -9,32 +9,33 @@ import (
 )
 
 type ListingDTO struct {
-	ID                uint64         `json:"id"`
-	ListingNo         string         `json:"listing_no"`
-	AccountID         uint64         `json:"account_id"`
-	OwnerID           uint64         `json:"owner_id"`
-	OwnerPhone        string         `json:"owner_phone,omitempty"`
-	OwnerNickname     string         `json:"owner_nickname,omitempty"`
-	Title             string         `json:"title"`
-	Description       string         `json:"description"`
-	GameName          string         `json:"game_name"`
-	ServerRegion      string         `json:"server_region"`
-	LoginPlatform     string         `json:"login_platform"`
-	RankLevel         string         `json:"rank_level"`
-	HafCoinAmount     int64          `json:"haf_coin_amount"`
-	AssetSummary      map[string]any `json:"asset_summary,omitempty"`
-	ScreenshotURLS    []string       `json:"screenshot_urls"`
-	CoverURL          string         `json:"cover_url"`
-	PriceCent         int64          `json:"price_cent"`
-	DepositAmountCent int64          `json:"deposit_amount_cent"`
-	IsAccelerated     bool           `json:"is_accelerated_sale"`
-	InTransaction     bool           `json:"in_transaction"`
-	Status            string         `json:"status"`
-	ReviewStatus      string         `json:"review_status"`
-	ReviewReason      string         `json:"review_reason"`
-	PublishedAt       *time.Time     `json:"published_at"`
-	CreatedAt         time.Time      `json:"created_at"`
-	UpdatedAt         time.Time      `json:"updated_at"`
+	ID                          uint64         `json:"id"`
+	ListingNo                   string         `json:"listing_no"`
+	AccountID                   uint64         `json:"account_id"`
+	OwnerID                     uint64         `json:"owner_id"`
+	OwnerPhone                  string         `json:"owner_phone,omitempty"`
+	OwnerNickname               string         `json:"owner_nickname,omitempty"`
+	Title                       string         `json:"title"`
+	Description                 string         `json:"description"`
+	GameName                    string         `json:"game_name"`
+	ServerRegion                string         `json:"server_region"`
+	LoginPlatform               string         `json:"login_platform"`
+	RankLevel                   string         `json:"rank_level"`
+	HafCoinAmount               int64          `json:"haf_coin_amount"`
+	AssetSummary                map[string]any `json:"asset_summary,omitempty"`
+	ScreenshotURLS              []string       `json:"screenshot_urls"`
+	CoverURL                    string         `json:"cover_url"`
+	PriceCent                   int64          `json:"price_cent"`
+	DepositAmountCent           int64          `json:"deposit_amount_cent"`
+	IsAccelerated               bool           `json:"is_accelerated_sale"`
+	InTransaction               bool           `json:"in_transaction"`
+	Status                      string         `json:"status"`
+	ReviewStatus                string         `json:"review_status"`
+	ReviewReason                string         `json:"review_reason"`
+	PublishedAt                 *time.Time     `json:"published_at"`
+	ListingGroupConversationID  uint64         `json:"listing_group_conversation_id,omitempty"`
+	CreatedAt                   time.Time      `json:"created_at"`
+	UpdatedAt                   time.Time      `json:"updated_at"`
 }
 
 type CreateRequest struct {

backend/internal/modules/listing/mutation.go

@@ -59,7 +59,19 @@ func (r *Repository) Create(ctx context.Context, ownerID uint64, req CreateReque
 		if err := tx.Create(&listing).Error; err != nil {
 			return err
 		}
+
+		// 发布提交时建发布群
+		var conversationID uint64
+		if r.chatCreator != nil {
+			convID, err := r.chatCreator.EnsureListingConversation(tx, listing)
+			if err != nil {
+				return err
+			}
+			conversationID = convID
+		}
+
 		dto = toDTO(account, listing)
+		dto.ListingGroupConversationID = conversationID
 		return nil
 	})
 	return dto, err

backend/internal/modules/listing/repository.go

@@ -6,16 +6,26 @@ import (
 	"time"
 
 	"gorm.io/gorm"
+	"hfb_sys/backend/internal/model"
 )
 
+// ListingChatCreator 发布群创建接口(由 chat 模块实现,避免直接依赖)
+type ListingChatCreator interface {
+	EnsureListingConversation(tx *gorm.DB, listing model.RentalListing) (conversationID uint64, err error)
+}
+
 type Repository struct {
 	db                 *gorm.DB
 	publicZoneCountsMu sync.Mutex
 	publicZoneCounts   publicZoneCountCache
+	chatCreator        ListingChatCreator
 }
 
-func NewRepository(db *gorm.DB) *Repository {
-	return &Repository{db: db}
+func NewRepository(db *gorm.DB, chatCreator ListingChatCreator) *Repository {
+	return &Repository{
+		db:          db,
+		chatCreator: chatCreator,
+	}
 }
 
 type publicZoneCountCache struct {