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/[id]/edit/page.tsx

@@ -121,7 +121,7 @@ function EditProjectContent({ projectId }: { projectId: string }) {
 
   // Fetch existing tags for suggestions
   const { data: existingTags } = trpc.project.getTags.useQuery({
-    roundId: project?.roundId,
+    roundId: project?.roundProjects?.[0]?.round?.id,
   })
 
   // Mutations
@@ -162,7 +162,7 @@ function EditProjectContent({ projectId }: { projectId: string }) {
         title: project.title,
         teamName: project.teamName || '',
         description: project.description || '',
-        status: project.status as UpdateProjectForm['status'],
+        status: (project.roundProjects?.[0]?.status ?? 'SUBMITTED') as UpdateProjectForm['status'],
         tags: project.tags || [],
       })
     }
@@ -197,6 +197,7 @@ function EditProjectContent({ projectId }: { projectId: string }) {
       teamName: data.teamName || null,
       description: data.description || null,
       status: data.status,
+      roundId: project?.roundProjects?.[0]?.round?.id,
       tags: data.tags,
     })
   }