Messaging: fix New Message dialog overflow on long recipient names

The recipient row's inner name+badge flex lacked min-w-0, so a long name
(e.g. a full association name) couldn't truncate — it widened the row,
pushed the badge out, and stretched the dialog (and its full-width search
field) past max-w-md. Add min-w-0 so the name truncates and the dialog
stays within bounds.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/messaging/ConversationList.tsx

@@ -367,7 +367,7 @@ function NewConversationDialog({ onSelectPartner }: { onSelectPartner: (id: stri
                       </AvatarFallback>
                     </Avatar>
                     <div className="flex-1 min-w-0">
-                      <div className="flex items-center gap-2">
+                      <div className="flex items-center gap-2 min-w-0">
                         <span className="text-sm font-medium truncate">{u.full_name || "Unknown User"}</span>
                         <Badge variant="outline" className="text-[10px] capitalize shrink-0">
                           {u.category === "board" ? "Board" : u.category}