The header builder must separate accepted fields from fields containing forbidden control characters. Implement the guard using the supplied policy without sending any network requests.
Build the implementation in Rust 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 name/value string pairs represented as objects. A valid name is nonempty ASCII letters, digits or hyphens; a valid value has no ASCII control characters except horizontal tab and no DEL (127). Return accepted records in order and rejected zero-based indices. Preserve duplicates and value whitespace. This intentionally uses a restricted header-name grammar. Nonstring fields must be rejected.
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.