Spec Kitty

Data model: Event write hygiene

No data shape changes. Every surviving writer writes the same row bytes (store.serialize_event_line).

• Status event log (kitty-specs/<mission>/status.events.jsonl): written only through status/store.py's atomic primitives. It is reached from emit.py (flat shell) and from coordination/status_service.append_event_stream_log (the BookkeepingTransaction funnel), plus the census families listed in status/_unsafe.ALLOWED_CALLERS.
• Invocation index (kitty-ops/ops-index.jsonl): a derived performance index, not an event log. It is written only by invocation/writer.InvocationWriter._append_to_index.
• Produce seam registry (status/adapters.py): three handler lists (status, lifecycle, resolved-binding). All are empty in open-core. Invariants:
• registration is idempotent by qualified name;
• every fire_* is non-raising and bounded by SPEC_KITTY_STATUS_FANOUT_TIMEOUT (default 10 s; a non-positive value runs the handler inline);
• an empty registry is a no-op.