Comprehensive admin UI stats audit: fix 16 display bugs

HIGH fixes:
- H1: Competition detail project count no longer double-counts across rounds
- H2: Rounds page header stats use unfiltered round set
- H3: Rounds page "eval" label corrected to "asgn" (assignment count)
- H4: Observer reports project count uses distinct analytics count
- H5: Awards eligibility count filters to only eligible=true (backend)
- H6: Round detail projectCount derived from projectStates for consistency
- H7: Deliberation hasVoted derived from votes array (was always undefined)

MEDIUM fixes:
- M1: Reports page round status badges use correct ROUND_ACTIVE/ROUND_CLOSED enums
- M2: Observer reports badges use ROUND_ prefix instead of stale STAGE_ prefix
- M3: Deliberation list status badges use correct VOTING/TALLYING/RUNOFF enums
- M4: Competition list/detail round count excludes special-award rounds (backend)
- M5: Messages page shows actual recipient count instead of hardcoded "1 user"

LOW fixes:
- L2: Observer analytics jurorCount scoped to round when roundId provided
- L3: Analytics round-scoped project count uses ProjectRoundState not assignments
- L4: JuryGroup delete audit log reports member count (not assignment count)
- L5: Project rankings include unevaluated projects at bottom instead of hiding

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

src/app/(admin)/admin/messages/page.tsx

@@ -592,7 +592,7 @@ export default function MessagesPage() {
                                 : msg.recipientType === 'ROUND_JURY'
                                   ? 'Round jury'
                                   : msg.recipientType === 'USER'
-                                    ? '1 user'
+                                    ? `${recipientCount || 1} user${recipientCount > 1 ? 's' : ''}`
                                     : msg.recipientType}
                             {recipientCount > 0 && ` (${recipientCount})`}
                           </TableCell>