✨ feat(epic-4): chemins narratifs, easter eggs, challenge et contact

Epic 4: Chemins Narratifs, Challenge & Contact

Stories implementees:
- 4.1: Composant ChoiceCards pour choix narratifs binaires
- 4.2: Sequence d'intro narrative avec Le Bug
- 4.3: Chemins narratifs differencies avec useNarrativePath
- 4.4: Table easter_eggs et systeme de detection (API + composable)
- 4.5: Easter eggs UI (popup, notification, collection)
- 4.6: Page challenge avec puzzle de code
- 4.7: Page revelation "Monde de Code"
- 4.8: Page contact avec formulaire et stats

Fichiers crees:
- Frontend: ChoiceCards, IntroSequence, ZoneEndChoice, EasterEggPopup,
  CodePuzzle, ChallengeSuccess, CodeWorld, et pages intro/challenge/revelation
- API: EasterEggController, Model, Migration, Seeder

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

frontend/app/components/feature/ChallengeSuccess.vue

@@ -0,0 +1,80 @@
+<template>
+  <div class="challenge-success text-center relative">
+    <!-- Celebration particles -->
+    <div class="particles absolute inset-0 overflow-hidden pointer-events-none">
+      <span
+        v-for="i in 20"
+        :key="i"
+        class="particle"
+        :style="{ '--delay': `${i * 0.1}s`, '--x': `${Math.random() * 100}%` }"
+      />
+    </div>
+
+    <div class="relative z-10">
+      <div class="text-6xl mb-4 animate-bounce" aria-hidden="true">*</div>
+
+      <h2 class="text-3xl font-ui font-bold text-sky-accent mb-4">
+        {{ $t('challenge.success') }}
+      </h2>
+
+      <p class="font-narrative text-xl text-sky-text mb-8">
+        {{ $t('challenge.successMessage') }}
+      </p>
+
+      <p class="text-sky-text/60">
+        {{ $t('challenge.redirecting') }}
+      </p>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+// No dependencies needed - pure CSS animation
+</script>
+
+<style scoped>
+.particles {
+  position: absolute;
+  width: 100%;
+  height: 100%;
+}
+
+.particle {
+  position: absolute;
+  width: 10px;
+  height: 10px;
+  border-radius: 50%;
+  animation: confetti 2s ease-out forwards;
+  animation-delay: var(--delay, 0s);
+  left: var(--x, 50%);
+  top: 50%;
+  opacity: 0;
+}
+
+.particle:nth-child(odd) {
+  background-color: var(--sky-accent, #fa784f);
+}
+
+.particle:nth-child(even) {
+  background-color: #3b82f6;
+}
+
+.particle:nth-child(3n) {
+  background-color: #10b981;
+}
+
+.particle:nth-child(4n) {
+  background-color: #f59e0b;
+}
+
+@keyframes confetti {
+  0% {
+    transform: translateY(0) rotate(0deg);
+    opacity: 1;
+  }
+  100% {
+    transform: translateY(-200px) rotate(720deg);
+    opacity: 0;
+  }
+}
+</style>