The text splitter uses encoded byte positions as though they were character positions. Repair it so the chunks preserve the input text and follow the defined character-based size limit.
Build the implementation in JavaScript 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 text and positive integer size. Split into consecutive chunks of at most size Unicode code points, retaining the final partial chunk. Python string indexing defines code points; grapheme clusters are not combined. Reject boolean/noninteger/nonpositive size.
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.