Add admin panel with CRUD endpoints and management UI

Add admin API endpoints for games, routes, pokemon, and route encounters
with full CRUD operations including bulk import. Build admin frontend
with game/route/pokemon management pages, navigation, and data tables.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/admin/AdminLayout.tsx

@@ -0,0 +1,39 @@
+import { NavLink, Outlet } from 'react-router-dom'
+
+const navItems = [
+  { to: '/admin/games', label: 'Games' },
+  { to: '/admin/pokemon', label: 'Pokemon' },
+]
+
+export function AdminLayout() {
+  return (
+    <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-8">
+      <h1 className="text-2xl font-bold mb-6">Admin Panel</h1>
+      <div className="flex gap-8">
+        <nav className="w-48 flex-shrink-0">
+          <ul className="space-y-1">
+            {navItems.map((item) => (
+              <li key={item.to}>
+                <NavLink
+                  to={item.to}
+                  className={({ isActive }) =>
+                    `block px-3 py-2 rounded-md text-sm font-medium ${
+                      isActive
+                        ? 'bg-blue-100 text-blue-700 dark:bg-blue-900 dark:text-blue-200'
+                        : 'hover:bg-gray-100 dark:hover:bg-gray-700'
+                    }`
+                  }
+                >
+                  {item.label}
+                </NavLink>
+              </li>
+            ))}
+          </ul>
+        </nav>
+        <div className="flex-1 min-w-0">
+          <Outlet />
+        </div>
+      </div>
+    </div>
+  )
+}