fix(persistence): migrate all pkg/persistence imports to plugins/infra/database and plugins/infra/cache

- Replace db.DB(ctx) with database.DB(ctx) from plugins/infra/database
- Replace db.Redis/db.PrefixedKey/db.GetJSON/db.SetJSON with cachepkg.* from plugins/infra/cache
- Replace pkg/persistence/idgen with pkg/idgen (already exists)
- Replace pkg/persistence/batchwriter with pkg/batchwriter (already exists)
- Replace pkg/persistence/migrator with pkg/migrator (already exists)
- Replace pkg/persistence/logstore with plugins/domain/risk_control/logstore
- Delete defunct pkg/{persistence,cap,message_gateway,push,shared,task}
- Fix vet issues: db alias in domain_test.go, driver_asynq_worker.TaskHandler reference
- Update Makefile architecture guard
- Update docs and skill references
- Update go.mod: gorilla/sessions promotion to direct dependency

plugins/domain/message_gateway/pairing_test.go

@@ -0,0 +1,33 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package message_gateway
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestGenerateCode_AlphabetAndLength(t *testing.T) {
+	code, err := GenerateCode()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(code) != 8 {
+		t.Fatalf("len=%d", len(code))
+	}
+	for _, r := range code {
+		if !strings.ContainsRune(CodeAlphabet, r) {
+			t.Fatalf("bad rune %q", r)
+		}
+	}
+}
+
+func TestNormalizeAndFormat(t *testing.T) {
+	if got := NormalizeCode("ab-cd-ef-gh"); got != "ABCDEFGH" {
+		t.Fatalf("got %q", got)
+	}
+	if got := FormatCode("ABCDEFGH"); got != "ABCD-EFGH" {
+		t.Fatalf("got %q", got)
+	}
+}