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

.agents/skills/file-upload/SKILL.md

@@ -84,7 +84,7 @@ import (
     "bytes"
 
     "github.com/Rain-kl/Wavelet/internal/apps/upload"
-    "github.com/Rain-kl/Wavelet/internal/model"
+    "github.com/Rain-kl/Wavelet/pkg/model"
 )
 
 func ingestMirrorFile(ctx context.Context, userID uint64, data []byte, hash, filename, mime, ext string) (model.Upload, error) {

.agents/skills/new-api/references/handler_example.go

@@ -6,7 +6,7 @@ package references
 import (
 	"net/http"
 
-	"github.com/Rain-kl/Wavelet/internal/shared/response"
+	"github.com/Rain-kl/Wavelet/pkg/response"
 	"github.com/gin-gonic/gin"
 )
 

.agents/skills/push-notification/SKILL.md

@@ -39,7 +39,7 @@ import (
 	"time"
 
 	"github.com/Rain-kl/Wavelet/internal/apps/admin/push"
-	"github.com/Rain-kl/Wavelet/internal/listener"
+	"github.com/Rain-kl/Wavelet/pkg/listener"
 )
 
 var NewUserRegistered = push.EventMetadata{
@@ -84,7 +84,7 @@ func Register() {
 在业务逻辑完成处（如 `internal/apps/user/routers.go`）仅 import `internal/listener` 并发射事件：
 
 ```go
-import "github.com/Rain-kl/Wavelet/internal/listener"
+import "github.com/Rain-kl/Wavelet/pkg/listener"
 
 func Register(c *gin.Context) {
 	// ... 注册成功逻辑 ...