Why: Replayed events, snapshot races, and source navigation must preserve authoritative work and user focus.
Evidence: SELF make evidence records 213 frontend tests, type checks, knip ratchet, and production build.
Impact: Uses the existing store for task revisions and gap replay; opens sources in the existing preview with version context.
Refs: fast-slow-u2-u3 Task 5; generated public contract types account for the measured knip baseline increase