Woody, Buzz, and the rest of the endearing playthings return to the big screen triumphantly in “Toy Story 3,” a moving and worthy addition to the successful series of movies. The time finally arrives when the toys’ owner, Andy, prepares to leave for college, signaling a turning point in the sentient collectibles’ secret lives. They find a renewed sense of purpose at a day care center, where they meet a number of toy residents. “Toy Story 3” delightfully reminds us of growing up, moving on, and sacrificing for the happiness of others. By the Story’s end, you’ll choke up, smile, and feel grateful.