chore(gomall/tutorial): save ch11 code after course #256

Job	Run time
resolve module	5s
compliant	19s
lint module (./gomall/common)	10s
lint module (./gomall/app/order)	18s
lint module (./gomall/app/cart)	12s
lint module (./gomall/app/user)	11s
lint module (./gomall/app/product)	11s
lint module (./gomall/app/frontend)	15s
lint module (./gomall/app/email)	16s
lint module (./gomall/app/payment)	11s
lint module (./gomall/app/checkout)	11s
lint module (./bookinfo)	17s
lint module (./open-payment-platform)	12s
lint module (./book-shop)	12s
lint module (./easy_note)	19s
	3m 19s

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