feat: arena bot sprites, boxing-style Fight Card page

- Arena page shows small sprite previews next to each bot's name
- Server returns archetype in fights list endpoint
- New /fight-card page with 3D perspective fight poster, neon signs,
  animated boxing gloves, fighter bobbing, VS pulse, undercard list
- Added FIGHT CARD to nav bar

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

frontend/src/router.ts

@@ -11,6 +11,11 @@ const routes = [
     name: 'arena',
     component: () => import('./pages/ArenaPage.vue'),
   },
+  {
+    path: '/fight-card',
+    name: 'fight-card',
+    component: () => import('./pages/FightCardPage.vue'),
+  },
   {
     path: '/arena/:fightId',
     name: 'fight',