We added a room to our house in 4S recently. The CC&R says the work must be completed within 6 months, but there is no ‘or else’. It took few days over 6 months (I spent the first 2 months waiting for the approval from the county and the last two months waiting for painters, the actual construction took 4 weeks) and there was no penalty. The HOA did note that I was late, but they took no action (I expected some of the deposit not to be returned).
I believe the county gave us 2 years to finish.
A friend had some construction done in San Marcos. He went about a week over the limit and he had to pay $500/day in penalties (and he did pay).