fix: show account name in upload select after selection

Base UI Select.Value renders the raw value prop (cuid) rather than
the item label. Pass the looked-up account name as children to
override it. Falls back to placeholder when no account matches.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/upload/UploadForm.tsx

@@ -97,7 +97,9 @@ export function UploadForm({ accounts }: Props) {
         ) : (
           <Select value={accountId} onValueChange={(v) => setAccountId(v ?? '')}>
             <SelectTrigger id="account" className="w-72">
-              <SelectValue placeholder="Select account" />
+              <SelectValue placeholder="Select account">
+                {accounts.find((a) => a.id === accountId)?.name}
+              </SelectValue>
             </SelectTrigger>
             <SelectContent>
               {accounts.map((a) => (