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

pkg/persistence/redis_test.go

@@ -0,0 +1,28 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package db
+
+import (
+	"testing"
+
+	"github.com/redis/go-redis/v9/maintnotifications"
+)
+
+func TestRedisMaintNotificationsConfig(t *testing.T) {
+	for _, test := range []struct {
+		name    string
+		enabled bool
+		want    maintnotifications.Mode
+	}{
+		{name: "disabled by default", enabled: false, want: maintnotifications.ModeDisabled},
+		{name: "auto when enabled", enabled: true, want: maintnotifications.ModeAuto},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			cfg := redisMaintNotificationsConfig(test.enabled)
+			if cfg.Mode != test.want {
+				t.Fatalf("maintenance notifications mode = %v, want %v", cfg.Mode, test.want)
+			}
+		})
+	}
+}