✨ 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/i18n/en.json

@@ -115,7 +115,15 @@
     "no_testimonials": "No testimonials yet",
     "cta_title": "Want to work together?",
     "cta_description": "Let's discuss your project and see how I can help.",
-    "cta_button": "Contact me"
+    "cta_button": "Contact me",
+    "dialogue_mode": "Dialogue",
+    "list_mode": "List",
+    "click_to_continue": "Click or press Space to continue...",
+    "previous": "Previous",
+    "next": "Next",
+    "finish": "Finish",
+    "go_to": "Go to testimonial",
+    "keyboard_hint": "Use \u2190 \u2192 arrows to navigate, Space to speed up"
   },
   "pages": {
     "projects": {