feat: battle system, state manager enhancements, engine and demo updates

src/App.vue

@@ -13,6 +13,8 @@ import AchievementToast from '@/components/AchievementToast.vue'
 import AchievementPanel from '@/components/AchievementPanel.vue'
 import AccessibilitySettings from '@/components/AccessibilitySettings.vue'
 import StoryGallery from '@/components/StoryGallery.vue'
+import BattleHUD from '@/components/BattleHUD.vue'
+import BattleResult from '@/components/BattleResult.vue'
 import { useGameEngine } from '@/composables/useGameEngine'
 import { useGameStore } from '@/stores/gameStore'
 import { useFullscreen } from '@/composables/useFullscreen'
@@ -346,6 +348,10 @@ init()
         <Transition name="prompt-toast">
           <div v-if="showPromptToast" class="prompt-toast">{{ promptToast }}</div>
         </Transition>
+        <BattleHUD
+          v-if="store.currentScene?.battleHUD"
+          :entries="store.currentScene!.battleHUD"
+        />
         <div v-if="started && !store.gameEnded && store.choices.length === 0" class="top-bar" :class="{ hidden: !showTopBar }">
           <button class="top-btn" @click="toggleFullscreen" :title="t('ui.fullscreen')">⛶</button>
           <button class="top-btn" @click="showPauseMenu = true" :title="t('ui.menu')">≡</button>
@@ -361,6 +367,11 @@ init()
         @skip="handleSkip"
         @speed-change="handleSpeedChange"
       />
+      <BattleResult
+        v-if="store.showBattleResult"
+        :result="store.battleResultData"
+        @continue="store.setShowBattleResult(false)"
+      />
       <MainMenu
         v-if="!started || store.gameEnded"
         :show-resume="!store.gameEnded && hasAutoSave"