Move wrap_line_chars and format_json_line from app.rs to core/io/wrap.rs with MAX_WRAP_INPUT_LEN guard. Add serde derives, pub getters, and extend_from_bytes() to LineIndex for incremental index building. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>