The arithmetic helper gives the wrong integer result for some negative operands. Repair its division behavior so the sign and rounding rules are consistent for every supported operand pair.
Build the implementation in C under /app, with /app/run.sh as its entry point. Read one JSON request from standard input and write one JSON result to standard output. Input has integer numerator and denominator. Return quotient truncated toward zero and remainder satisfying numerator = quotient*denominator + remainder. Avoid floating-point conversion so arbitrarily large integers work. Reject zero denominator or boolean/noninteger operands.
Reject inputs that violate an explicit validation rule with exit status 2, no standard output, and {"error":"invalid_input"} on standard error. For valid input, exit with status 0. Keep the implementation reusable for new inputs; it must work offline and must not depend on the example data being the only data it receives.
Repair or replace the unfinished /app/run.sh and add source files under /app. Malformed JSON must use the same invalid-input response. Do not read /tests or /oracle from the application.