fix: save roundId on admin file upload and group assignments by round

The admin upload flow accepted roundId but never wrote it to the
ProjectFile record, causing all admin-uploaded files to appear under
"General". Fixed the create call, the listByProject filter, and the
listByProjectForStage grouping to also use the direct roundId field.

Jury assignments on the project detail page are now grouped by round
with per-round completion counts instead of a flat list.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/jury/multi-window-doc-viewer.tsx

@@ -54,8 +54,8 @@ export function MultiWindowDocViewer({ roundId, projectId }: MultiWindowDocViewe
   }> = {}
 
   for (const file of files) {
-    const roundName = file.requirement?.round?.name ?? 'General'
-    const rId = file.requirement?.round?.id ?? null
+    const rId = file.requirement?.round?.id ?? (file as any).roundId ?? null
+    const roundName = file.requirement?.round?.name ?? (rId ? 'Round Files' : 'General')
     const sortOrder = file.requirement?.round?.sortOrder ?? 999
     if (!groupMap[roundName]) {
       groupMap[roundName] = { roundId: rId, roundName, sortOrder, files: [] }