A summer breeze sweeps across the patio at Joe T. Garcia’s, and water splashes into the sun-kissed pool where generations of this proud family came of age. Tranquility and tradition are the main draws here, but it’s a well-oiled kitchen operation, perfected over eight decades, that keeps the Mexican dishes and margaritas flowing at Fort Worth’s busiest and best-known restaurant. Rarely has an 18-hour workday been made to look so easy.