SAN FRANCISCO — Every morning Turtle Brennan, a research engineer who lives here in the Mission District, buys a coffee from Ritual Roasters, a locally based coffee chain. Since the stay-at-home order, he’s also been getting a pastry so he can support the bakeries it works with. He calls restaurants and picks up his food directly, and he still buys books from Borderlands — the same local bookstore he’s been visiting regularly for more than 20 years.