✨ Add DialoguePNJ component with typewriter effect (Story 2.7)

- Create useReducedMotion composable for motion preferences
- Create useTypewriter composable with accelerate/skip support
- Add DialoguePNJ component with Zelda-style dialogue system
- Add personality-based styling (sage, sarcastique, enthousiaste, professionnel)
- Implement keyboard navigation (arrows, space)
- Add toggle between dialogue and list view modes
- Add i18n translations for dialogue UI

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

frontend/app/composables/useReducedMotion.ts

@@ -0,0 +1,20 @@
+export function useReducedMotion() {
+  const reducedMotion = ref(false)
+
+  if (import.meta.client) {
+    const mediaQuery = window.matchMedia('(prefers-reduced-motion: reduce)')
+    reducedMotion.value = mediaQuery.matches
+
+    const handler = (e: MediaQueryListEvent) => {
+      reducedMotion.value = e.matches
+    }
+
+    mediaQuery.addEventListener('change', handler)
+
+    onUnmounted(() => {
+      mediaQuery.removeEventListener('change', handler)
+    })
+  }
+
+  return readonly(reducedMotion)
+}