Silicon Valley Hiring Perks: Meals, iPads and a Cubicle for Spot SAN FRANCISCO — Eric Firestone began a new job at a Web start-up here three weeks ago, and he’s already thinking about what he might do next. But that’s just fine with his new employer. The company, a service to turn cellphones into credit card readers, lured Mr. Firestone from Apple partly with an unusual pitch: it promised to give