SAN FRANCISCO — The big banks and Silicon Valley are waging an escalating battle over your personal financial data, including the amount you spent on dinner last week and how much you are paying for your mortgage.Technology start-ups like Mint and Betterment have been building services that pull together your bank account and credit card records — after you supply the passwords.But now big banks are making a concerted push to set new restrictions on how technology companies can get access to this personal financial data, in some cases refusing to pass along information like the fees and int