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>

prisma/cleanup-all-dummy.ts

@@ -10,18 +10,18 @@ async function cleanup() {
       id: true,
       name: true,
       slug: true,
-      projects: { select: { id: true, title: true } },
-      _count: { select: { projects: true } }
+      roundProjects: { select: { id: true, projectId: true, project: { select: { id: true, title: true } } } },
+      _count: { select: { roundProjects: true } }
     }
   })
 
   console.log(`Found ${rounds.length} rounds:`)
   for (const round of rounds) {
-    console.log(`- ${round.name} (slug: ${round.slug}): ${round._count.projects} projects`)
+    console.log(`- ${round.name} (slug: ${round.slug}): ${round._count.roundProjects} projects`)
   }
 
   // Find rounds with 9 or fewer projects (dummy data)
-  const dummyRounds = rounds.filter(r => r._count.projects <= 9)
+  const dummyRounds = rounds.filter(r => r._count.roundProjects <= 9)
 
   if (dummyRounds.length > 0) {
     console.log(`\nDeleting ${dummyRounds.length} dummy round(s)...`)
@@ -29,10 +29,16 @@ async function cleanup() {
     for (const round of dummyRounds) {
       console.log(`\nProcessing: ${round.name}`)
 
-      const projectIds = round.projects.map(p => p.id)
+      const projectIds = round.roundProjects.map(rp => rp.projectId)
 
       if (projectIds.length > 0) {
-        // Delete team members first
+        // Delete round-project associations first
+        const rpDeleted = await prisma.roundProject.deleteMany({
+          where: { roundId: round.id }
+        })
+        console.log(`  Deleted ${rpDeleted.count} round-project associations`)
+
+        // Delete team members
         const teamDeleted = await prisma.teamMember.deleteMany({
           where: { projectId: { in: projectIds } }
         })