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/projects/page.tsx

@@ -350,9 +350,9 @@ export default function ProjectsPage() {
                     </TableCell>
                     <TableCell>
                       <div>
-                        <p>{project.round.name}</p>
+                        <p>{project.roundProjects?.[0]?.round?.name ?? '-'}</p>
                         <p className="text-sm text-muted-foreground">
-                          {project.round.program?.name}
+                          {project.program?.name}
                         </p>
                       </div>
                     </TableCell>
@@ -365,9 +365,9 @@ export default function ProjectsPage() {
                     </TableCell>
                     <TableCell>
                       <Badge
-                        variant={statusColors[project.status] || 'secondary'}
+                        variant={statusColors[project.roundProjects?.[0]?.status ?? 'SUBMITTED'] || 'secondary'}
                       >
-                        {project.status.replace('_', ' ')}
+                        {(project.roundProjects?.[0]?.status ?? 'SUBMITTED').replace('_', ' ')}
                       </Badge>
                     </TableCell>
                     <TableCell className="relative z-10 text-right">
@@ -431,11 +431,11 @@ export default function ProjectsPage() {
                           </CardTitle>
                           <Badge
                             variant={
-                              statusColors[project.status] || 'secondary'
+                              statusColors[project.roundProjects?.[0]?.status ?? 'SUBMITTED'] || 'secondary'
                             }
                             className="shrink-0"
                           >
-                            {project.status.replace('_', ' ')}
+                            {(project.roundProjects?.[0]?.status ?? 'SUBMITTED').replace('_', ' ')}
                           </Badge>
                         </div>
                         <CardDescription>{project.teamName}</CardDescription>
@@ -445,7 +445,7 @@ export default function ProjectsPage() {
                   <CardContent className="space-y-3">
                     <div className="flex items-center justify-between text-sm">
                       <span className="text-muted-foreground">Round</span>
-                      <span>{project.round.name}</span>
+                      <span>{project.roundProjects?.[0]?.round?.name ?? '-'}</span>
                     </div>
                     <div className="flex items-center justify-between text-sm">
                       <span className="text-muted-foreground">Assignments</span>