Fix voting gate to use round status, make eval doc uploads toggleable

Voting check now uses round.status === ROUND_ACTIVE instead of requiring
windowOpenAt/windowCloseAt date range, fixing manual open/reopen scenarios.
Added requireDocumentUpload toggle (default off) to evaluation round config
so rounds reusing prior-round documents don't need file requirements.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/(jury)/jury/page.tsx

@@ -357,12 +357,7 @@ async function JuryDashboardContent() {
                       const evaluation = assignment.evaluation
                       const isCompleted = evaluation?.status === 'SUBMITTED'
                       const isDraft = evaluation?.status === 'DRAFT'
-                      const isVotingOpen =
-                        assignment.round.status === 'ROUND_ACTIVE' &&
-                        assignment.round.windowOpenAt &&
-                        assignment.round.windowCloseAt &&
-                        new Date(assignment.round.windowOpenAt) <= now &&
-                        new Date(assignment.round.windowCloseAt) >= now
+                      const isVotingOpen = assignment.round.status === 'ROUND_ACTIVE'
 
                       return (
                         <div