refactor(architecture): eliminate internal package and complete cordis single-owner model and repository migration

- Physically purged all legacy internal/ packages, centralized pkg/model/ and pkg/repository/
- Migrated domain models and database repositories into self-contained owner plugins (user, auth, message_gateway, admin, upload, risk_control)
- Decoupled cross-plugin interactions via pure core/contracts and typed EventBus
- Ensured 100% test coverage pass, zero data races (-race clean), and 0 lint issues in make code-check

plugins/domain/auth/models.go

@@ -12,7 +12,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/Rain-kl/Wavelet/internal/model"
+	"github.com/Rain-kl/Wavelet/core/contracts"
 )
 
 var authSourceNamePattern = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9_-]{0,79}$`)
@@ -162,8 +162,8 @@ type BasicUserInfo struct {
 	Location           string `json:"location"`
 }
 
-// BuildBasicUserInfo 将 User 模型转换为 BasicUserInfo
-func BuildBasicUserInfo(user *model.User, needChange bool) BasicUserInfo {
+// BuildBasicUserInfo 将 UserDTO 转换为 BasicUserInfo
+func BuildBasicUserInfo(user *contracts.UserDTO, needChange bool) BasicUserInfo {
 	if user == nil {
 		return BasicUserInfo{}
 	}