Security: unmark-not-participating now validates the result exists, belongs
to this event, and is actually a DNP row before deleting. mark-not-participating
now returns a user-friendly error on duplicate-key constraint violations.
Code quality: extract shared getExcludedByEventMap() utility to event-result
model, eliminating the duplicated 20-line exclusion-loading block that was
copy-pasted into all three simulators. Fix hasParticipantResult() to exclude
notParticipating rows so it correctly reflects actual competition participation.
Remove optional chaining on the non-optional notParticipatingIds field in the
admin UI. Fix misleading empty-state message.
Tests: replace the misleading first tennis DNP test (which never used the
activeIds variable it created) with a test that explicitly validates the
fallback behaviour when too few players remain after exclusion. Add three CS2
DNP tests covering the excluded-team-gets-zero-QP path, the redistribution
of wins, and per-event pool independence.
https://claude.ai/code/session_01HxNPLEXzr5Km3suWrJe2F9
ff116961f7