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/App.tsx

@@ -1,6 +1,8 @@
-import { Routes, Route } from 'react-router-dom'
+import { Routes, Route, Navigate } from 'react-router-dom'
 import { Layout } from './components'
+import { AdminLayout } from './components/admin'
 import { Home, NewRun, RunList, RunDashboard, RunEncounters } from './pages'
+import { AdminGames, AdminGameDetail, AdminPokemon, AdminRouteDetail } from './pages/admin'
 
 function App() {
   return (
@@ -11,6 +13,13 @@ function App() {
         <Route path="runs/new" element={<NewRun />} />
         <Route path="runs/:runId" element={<RunDashboard />} />
         <Route path="runs/:runId/encounters" element={<RunEncounters />} />
+        <Route path="admin" element={<AdminLayout />}>
+          <Route index element={<Navigate to="/admin/games" replace />} />
+          <Route path="games" element={<AdminGames />} />
+          <Route path="games/:gameId" element={<AdminGameDetail />} />
+          <Route path="games/:gameId/routes/:routeId" element={<AdminRouteDetail />} />
+          <Route path="pokemon" element={<AdminPokemon />} />
+        </Route>
       </Route>
     </Routes>
   )