Several event sources already produce sorted streams. Finish the merge so equal-valued events keep the required source order and the output retains enough provenance to identify their origin.
Build the implementation in Go 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 streams containing records with integer time and JSON value. Each stream must be nondecreasing by time. Return records with time, value, source (stream index), and offset (index within stream), sorted by time then source then offset. Preserve duplicate records. Reject decreasing timestamps or boolean/noninteger times.
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.