feat: add wallet settlement audit flow

apps/api/internal/store/tx.go

@@ -0,0 +1,19 @@
+package store
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+)
+
+type Tx interface {
+	Exec(ctx context.Context, sql string, arguments ...any) (pgconn.CommandTag, error)
+	QueryRow(ctx context.Context, sql string, args ...any) pgx.Row
+}
+
+func (s *Store) InTx(ctx context.Context, fn func(Tx) error) error {
+	return pgx.BeginFunc(ctx, s.pool, func(tx pgx.Tx) error {
+		return fn(tx)
+	})
+}