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/cap/middleware.go

@@ -6,7 +6,7 @@ package cap
 import (
 	"github.com/gin-gonic/gin"
 
-	"github.com/Rain-kl/Wavelet/internal/shared/response"
+	"github.com/Rain-kl/Wavelet/pkg/response"
 )
 
 // VerifyMiddleware returns a Gin middleware that checks and consumes the X-Cap-Token header.