I don't have much to add as I agree with others that according to the HOA you did nothing wrong (and thus should be protected), but I'm wondering why she would be so bothered by you working on your car with the garage door open. Were you being excessivly loud or doing it so late at night as to disturb her? It just sounds to me like she is a little batty, but if it were late enough at night I suppose that could be held against you.