✨ Add testimonials page with personality-styled cards (Story 2.6)

- Add testimonials table migration with personality enum
- Create Testimonial model with HasTranslations trait
- Add TestimonialSeeder with 4 test testimonials
- Create TestimonialController and TestimonialResource
- Add useFetchTestimonials composable
- Create TestimonialCard component with personality-based styling
- Add temoignages.vue page with loading/error states
- Add testimonials translations in FR/EN

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

frontend/i18n/fr.json

@@ -108,6 +108,15 @@
     "load_projects_error": "Impossible de charger les projets li\u00e9s",
     "no_related_projects": "Aucun projet n'utilise encore cette comp\u00e9tence"
   },
+  "testimonials": {
+    "page_title": "T\u00e9moignages | Skycel",
+    "page_description": "D\u00e9couvrez ce que disent mes collaborateurs et clients de mon travail.",
+    "load_error": "Impossible de charger les t\u00e9moignages...",
+    "no_testimonials": "Aucun t\u00e9moignage pour le moment",
+    "cta_title": "Envie de travailler ensemble ?",
+    "cta_description": "Discutons de votre projet et voyons comment je peux vous aider.",
+    "cta_button": "Me contacter"
+  },
   "pages": {
     "projects": {
       "title": "Projets",