Bridgeport climbs away from the harbor in short steep blocks, and every one of them hides a patch of green behind the house — a strip of side yard, a square of front lawn holding its own between the sidewalk slate and the porch steps. Aqua-Lawn Inc. keeps those lawns cut and tended through the long stretch from the first warm week in April to the last mild afternoon in November. There is real pride in the plain version of this work: an even cut, a clean edge along the walk, clippings gone and the yard looking cared for from the street. It is lawn care for a city that has always found room for grass wherever the brick lets it through.