Decouple projects from rounds with RoundProject join table

Projects now exist at the program level instead of being locked to a
single round. A new RoundProject join table enables many-to-many
relationships with per-round status tracking. Rounds have sortOrder
for configurable progression paths.

- Add RoundProject model, programId on Project, sortOrder on Round
- Migration preserves existing data (roundId -> RoundProject entries)
- Update all routers to query through RoundProject join
- Add assign/remove/advance/reorder round endpoints
- Add Assign, Advance, Remove Projects dialogs on round detail page
- Add round reorder controls (up/down arrows) on rounds list
- Show all rounds on project detail page

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

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

@@ -112,11 +112,11 @@ async function DashboardStats({ editionId, sessionName }: DashboardStatsProps) {
       where: { programId: editionId },
     }),
     prisma.project.count({
-      where: { round: { programId: editionId } },
+      where: { programId: editionId },
     }),
     prisma.project.count({
       where: {
-        round: { programId: editionId },
+        programId: editionId,
         createdAt: { gte: sevenDaysAgo },
       },
     }),
@@ -149,7 +149,7 @@ async function DashboardStats({ editionId, sessionName }: DashboardStatsProps) {
       include: {
         _count: {
           select: {
-            projects: true,
+            roundProjects: true,
             assignments: true,
           },
         },
@@ -161,31 +161,33 @@ async function DashboardStats({ editionId, sessionName }: DashboardStatsProps) {
       },
     }),
     prisma.project.findMany({
-      where: { round: { programId: editionId } },
+      where: { programId: editionId },
       orderBy: { createdAt: 'desc' },
       take: 8,
       select: {
         id: true,
         title: true,
         teamName: true,
-        status: true,
         country: true,
         competitionCategory: true,
         oceanIssue: true,
         logoKey: true,
         createdAt: true,
         submittedAt: true,
-        round: { select: { name: true } },
+        roundProjects: {
+          select: { status: true, round: { select: { name: true } } },
+          take: 1,
+        },
       },
     }),
     prisma.project.groupBy({
       by: ['competitionCategory'],
-      where: { round: { programId: editionId } },
+      where: { programId: editionId },
       _count: true,
     }),
     prisma.project.groupBy({
       by: ['oceanIssue'],
-      where: { round: { programId: editionId } },
+      where: { programId: editionId },
       _count: true,
     }),
   ])
@@ -392,7 +394,7 @@ async function DashboardStats({ editionId, sessionName }: DashboardStatsProps) {
                               </Badge>
                             </div>
                             <p className="text-sm text-muted-foreground">
-                              {round._count.projects} projects &middot; {round._count.assignments} assignments
+                              {round._count.roundProjects} projects &middot; {round._count.assignments} assignments
                               {round.totalEvals > 0 && (
                                 <> &middot; {round.evalPercent}% evaluated</>
                               )}
@@ -459,10 +461,10 @@ async function DashboardStats({ editionId, sessionName }: DashboardStatsProps) {
                               {truncate(project.title, 45)}
                             </p>
                             <Badge
-                              variant={statusColors[project.status] || 'secondary'}
+                              variant={statusColors[project.roundProjects[0]?.status ?? 'SUBMITTED'] || 'secondary'}
                               className="shrink-0 text-[10px] px-1.5 py-0"
                             >
-                              {project.status.replace('_', ' ')}
+                              {(project.roundProjects[0]?.status ?? 'SUBMITTED').replace('_', ' ')}
                             </Badge>
                           </div>
                           <p className="text-xs text-muted-foreground mt-0.5">