feat(admin): add admin endpoint to list user devices with JPush registration IDs

- Add AdminDeviceTokenResponse DTO including push_token (RegistrationID) for push debugging
- Add DeviceTokenToAdminResponse and DeviceTokensToAdminResponse converters
- Inject PushService into AdminUserHandler for retrieving user devices
- Register GET /api/v1/admin/users/:id/devices route for querying target user's device tokens

internal/dto/dto.go

@@ -499,6 +499,22 @@ type DeviceTokenResponse struct {
 	CreatedAt  time.Time `json:"created_at"`
 }
 
+// AdminDeviceTokenResponse 管理端设备Token响应
+// 相比 DeviceTokenResponse，额外包含 user_id 与 push_token（即 JPush RegistrationID），
+// 供后台查询用户设备 registration_id 使用。
+type AdminDeviceTokenResponse struct {
+	ID         int64     `json:"id"`
+	UserID     string    `json:"user_id"`
+	DeviceID   string    `json:"device_id"`
+	DeviceType string    `json:"device_type"`
+	PushToken  string    `json:"push_token,omitempty"` // JPush RegistrationID
+	IsActive   bool      `json:"is_active"`
+	DeviceName string    `json:"device_name,omitempty"`
+	LastUsedAt time.Time `json:"last_used_at,omitzero"`
+	CreatedAt  time.Time `json:"created_at"`
+	UpdatedAt  time.Time `json:"updated_at"`
+}
+
 // ==================== 推送记录 DTOs ====================
 
 // PushRecordResponse 推送记录响应

internal/dto/message_converter.go

@@ -199,3 +199,34 @@ func DeviceTokensToResponse(tokens []*model.DeviceToken) []*DeviceTokenResponse
 	}
 	return result
 }
+
+// DeviceTokenToAdminResponse 将DeviceToken转换为管理端响应（含 registration_id）
+func DeviceTokenToAdminResponse(token *model.DeviceToken) *AdminDeviceTokenResponse {
+	if token == nil {
+		return nil
+	}
+	resp := &AdminDeviceTokenResponse{
+		ID:         token.ID,
+		UserID:     token.UserID,
+		DeviceID:   token.DeviceID,
+		DeviceType: string(token.DeviceType),
+		PushToken:  token.PushToken,
+		IsActive:   token.IsActive,
+		DeviceName: token.DeviceName,
+		CreatedAt:  token.CreatedAt,
+		UpdatedAt:  token.UpdatedAt,
+	}
+	if token.LastUsedAt != nil {
+		resp.LastUsedAt = *token.LastUsedAt
+	}
+	return resp
+}
+
+// DeviceTokensToAdminResponse 将DeviceToken列表转换为管理端响应列表
+func DeviceTokensToAdminResponse(tokens []*model.DeviceToken) []*AdminDeviceTokenResponse {
+	result := make([]*AdminDeviceTokenResponse, 0, len(tokens))
+	for _, token := range tokens {
+		result = append(result, DeviceTokenToAdminResponse(token))
+	}
+	return result
+}