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/rounds/[id]/live-voting/page.tsx

@@ -180,7 +180,7 @@ function LiveVotingContent({ roundId }: { roundId: string }) {
       if (storedOrder.length > 0) {
         setProjectOrder(storedOrder)
       } else {
-        setProjectOrder(sessionData.round.projects.map((p) => p.id))
+        setProjectOrder(sessionData.round.roundProjects.map((rp) => rp.project.id))
       }
     }
   }, [sessionData])
@@ -253,7 +253,7 @@ function LiveVotingContent({ roundId }: { roundId: string }) {
     )
   }
 
-  const projects = sessionData.round.projects
+  const projects = sessionData.round.roundProjects.map((rp) => rp.project)
   const sortedProjects = projectOrder
     .map((id) => projects.find((p) => p.id === id))
     .filter((p): p is Project => !!p)