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/check-data.ts

@@ -8,23 +8,23 @@ async function check() {
 
   const rounds = await prisma.round.findMany({
     include: {
-      _count: { select: { projects: true } }
+      _count: { select: { roundProjects: true } }
     }
   })
 
   for (const r of rounds) {
     console.log(`Round: ${r.name} (id: ${r.id})`)
-    console.log(`  Projects: ${r._count.projects}`)
+    console.log(`  Projects: ${r._count.roundProjects}`)
   }
 
-  // Check if projects have roundId set
-  const projectsWithRound = await prisma.project.findMany({
-    select: { id: true, title: true, roundId: true },
+  // Check if projects have programId set
+  const sampleProjects = await prisma.project.findMany({
+    select: { id: true, title: true, programId: true },
     take: 5
   })
   console.log('\nSample projects:')
-  for (const p of projectsWithRound) {
-    console.log(`  ${p.title}: roundId=${p.roundId}`)
+  for (const p of sampleProjects) {
+    console.log(`  ${p.title}: programId=${p.programId}`)
   }
 }