CARACAS, Venezuela — The death toll from nearly four months of antigovernment protests climbed to at least 113 on Friday as Venezuela’s opposition called on backers to defy a protest ban ahead of a vote to launch a rewrite of the constitution. Residents of the capital, Caracas, lined up for hours at grocery stores and banks to stockpile food and cash before what many expected would be a chaotic weekend. Protesters say the election of a constitutional assembly Sunday will allow President Nicolas Maduro to eliminate checks and balances and replace Venezuela’s democratic system with an authoritarian, single-party government.