Introduce solstone-core-callosum as the owner of the Callosum wire envelope, the mixed events.jsonl durable-file model, its tolerant reader, its journal-io writer, and the generated registry fixture accessor. Migrate ingest reads and writes to that crate and remove the superseded segment sidecars writer. Read event files from raw fs::read bytes split on b'\n', never read_to_string, so a torn multibyte UTF-8 tail is skipped without losing valid rows. Return wrong_family, unparseable, and unrecognized counts through crate-local report structs rather than extending journal-io read_jsonl or logging skips. Refuse a missing or non-directory segment path with CallosumWriteError::SegmentDirectoryMissing before journal-io append can create it. Retire ReasonCode::IngestEventLogMalformed: malformed device_ingest rows are nonfatal counted rows. Rename manifest_surfaces_malformed_device_ingest_events to manifest_skips_malformed_device_ingest_events and assert HTTP 200 with the row skipped.