The current search routine mishandles repeated values at the ends of a sorted sequence. Repair the source so it returns the required boundaries without breaking the empty and absent-value cases.
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 a nondecreasing integer values list and integer target. Return inclusive first and last matching indices, or [-1,-1] when absent. Reject an unsorted list. Repair the starter so duplicate spans and missing targets work.
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.