Add auth system with invite-only registration and admin roles

JWT-based auth (hono/jwt + bcrypt), anonymous-first flow preserved.
Registration requires invite code when REQUIRE_INVITE=true. Admin
user seeded on startup (admin/admin, forced password reset). Login
accepts email or username. Admin invitations management page in
sidebar. Regular users get invite-a-friend button when USER_INVITATIONS > 0.
Frontend gate screen blocks game access for unregistered users with
invite code entry, registration, login, and password reset flows.

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

apps/web/src/pages/SettingsPage.tsx

@@ -1,6 +1,7 @@
 import { useRef, useState } from 'react';
 import { useGameStore } from '@/store';
 import { ConfirmModal } from '@/components/common/ConfirmModal';
+import { getTokenPayload, isRegistered, isAdmin } from '@/lib/api';
 
 export function SettingsPage() {
   const settings = useGameStore((s) => s.meta.settings);
@@ -63,10 +64,45 @@ export function SettingsPage() {
     window.location.reload();
   };
 
+  const payload = getTokenPayload();
+  const registered = isRegistered();
+  const admin = isAdmin();
+
   return (
     <div className="space-y-6 max-w-2xl">
       <h2 className="text-2xl font-bold">Settings</h2>
 
+      <div className="bg-surface-900 border border-surface-700 rounded-xl p-4 space-y-4">
+        <h3 className="font-semibold">Account</h3>
+        {registered ? (
+          <div className="space-y-2">
+            {payload?.email && (
+              <div className="flex items-center justify-between">
+                <div>
+                  <div className="text-sm">Email</div>
+                  <div className="text-xs text-surface-400">{payload.email}</div>
+                </div>
+              </div>
+            )}
+            {payload?.username && (
+              <div className="flex items-center justify-between">
+                <div>
+                  <div className="text-sm">Username</div>
+                  <div className="text-xs text-surface-400">{payload.username}</div>
+                </div>
+              </div>
+            )}
+            {admin && (
+              <div className="flex items-center gap-2">
+                <span className="text-xs px-2 py-0.5 rounded-full bg-accent/20 text-accent font-medium">Admin</span>
+              </div>
+            )}
+          </div>
+        ) : (
+          <div className="text-sm text-surface-400">Playing as guest.</div>
+        )}
+      </div>
+
       <div className="bg-surface-900 border border-surface-700 rounded-xl p-4 space-y-4">
         <h3 className="font-semibold">Game</h3>