Repeated requests with the same identifier should replay the accepted receipt, while conflicting reuse must be rejected. Finish the store so retries cannot overwrite the original accepted result.
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 an ordered list with id string and JSON payload. The first occurrence assigns the next integer receipt starting at one. A repeat ID with equal JSON payload reuses its receipt; reject a different payload for that ID. Object key order is irrelevant, array order matters, and JSON booleans differ from numbers. Return receipt IDs in input order.
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.