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/(public)/my-submission/[id]/submission-detail-client.tsx

@@ -132,7 +132,7 @@ export function SubmissionDetailClient() {
             </Badge>
           </div>
           <p className="text-muted-foreground">
-            {project.round.program.year} Edition - {project.round.name}
+            {project.roundProjects?.[0]?.round?.program?.year ? `${project.roundProjects[0].round.program.year} Edition` : ''}{project.roundProjects?.[0]?.round?.name ? ` - ${project.roundProjects[0].round.name}` : ''}
           </p>
         </div>
       </div>