None of these three tables gained their own user_id column -- they're
always accessed through a specific activity, so ownership is checked via a
join/subquery against activities.user_id instead.
Manual assignments are the user's definitive word and Race assignments come
from a hard Garmin fact (eventType.typeKey), not a retunable rule -- neither
is ever touched by reclassify again, and Race can no longer be set by hand
via the review queue. Adds an Activities page so this locked/unlocked status
is visible per workout, since Review Queue only ever showed unresolved items.
