The batch export needs whole minor units, but its source amounts are decimal strings. Finish the conversion so rounding and the reported residue are exact rather than dependent on binary floating point.
Build the implementation in Java 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 is a list of finite decimal strings. Round each amount to cents using decimal half-up (ties away from zero), sum integer cents, and report residue as the original total minus the rounded total formatted to four decimal places with half-up. Reject malformed or nonfinite decimals. Input precision is at most four fractional digits and absolute values at most one million.
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.