It's a tax that could hit Seattleites where it really hurts: their coffee mugs. A group of child-care advocates, seeking more money for early education, filed an initiative Friday that would place a 10-cent city tax on Seattle's lifeblood -- espresso drinks. But in Seattle, where voters have already voted to tax their tobacco, their meals and their hotel rooms, among other things, initial word of the proposal caused barely a jolt among the area's latte lovers. "Coffee, in a way, it's kind of a luxury item," said Patty Grazini, who frequents the Diva Espresso Bar in Seattle's Greenwood district....