The prices of homes at the Jersey Shore have almost doubled since the pandemic and low inventory is continuing to push up the cost of a coveted beach house escape, agents say. “People who have been in their home for four, five, six, seven years have 2.5% to 3% interest rates. They’re unwilling to move up to the next level” and buy a more expensive house that will come with a higher interest rate, said Michael Skea of Ward Wight Sotheby’s International Realty. “Folks are renovating their existing home, maintaining their lower interest rate and maybe expanding the footprint of their home to acco…