Add project reports section and fix mobile overflow issues

- Add project-wide reporting table with scope selector (all rounds / per round)
- Fix horizontal overflow on mobile (body, admin sidebar, logo truncation)
- Make members header and reports tabs responsive with flex-wrap

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

src/components/admin/members-content.tsx

@@ -148,14 +148,14 @@ export function MembersContent() {
   return (
     <div className="space-y-6">
       {/* Header */}
-      <div className="flex items-center justify-between">
-        <div>
+      <div className="flex items-center justify-between flex-wrap gap-4">
+        <div className="min-w-0">
           <h1 className="text-2xl font-semibold tracking-tight">Members</h1>
           <p className="text-muted-foreground">
             Manage jury members, mentors, observers, and admins
           </p>
         </div>
-        <Button asChild>
+        <Button asChild className="w-full sm:w-auto shrink-0">
           <Link href="/admin/members/invite">
             <Plus className="mr-2 h-4 w-4" />
             Add Member