Spec Kitty

Mission Run: Event write hygiene: retire dead write doors and private events imports

Remove dead event-log write doors and core's private spec-kitty-events import, and give the status produce seam transport-neutral names.

Ahead of the one-canonical-writer work (ADR 2026-10-14-1), core still carries write doors nobody uses, a private library import that a lock refresh could turn into a break, and hosted-era 'saas' names on the event produce seam. This mission deletes them behind red-first gates without changing behaviour, so the remaining write surface is exactly what the canonical writer will wrap.