Planning and politics are inseparable in San Francisco, especially at election time — which is why, on a gorgeous Sunday morning in North Beach, a half-dozen sign-waving protesters bickered with their city supervisor while city planners stood awkwardly a few feet away. The event was billed as a “mobile workshop” to let residents ask about how various planning issues might affect their neighborhood and — if that weren’t inducement enough on a day where the competition included Hardly Strictly Bluegrass and the Castro Street Fair — talk with planning staff on a one-to-one basis.