As a foreigner living in a, erm, foreign land, one of the holy grails of getting an intimate glimpse into local culture is receiving an invitation to someone’s home. Most cities feel impenetrable unless you know a local. Sometimes, they open their doors to you (The Italians offer their mothers, aunts and grandmothers and their regional Home Food to hungry visitors); sometimes they bring their domestic lives out onto the street to you (In Mumbai, the porch of a motor workshop doubles up as an airy platform for a toddler’s …