Sprint 5 : integration et production -- securite, performance, API publique, documentation

Backend: rate limiter, security headers, blockchain cache service avec RPC,
public API (7 endpoints read-only), WebSocket auth + heartbeat, DB connection
pooling, structured logging, health check DB. Frontend: API retry/timeout,
WebSocket auth + heartbeat + typed events, notifications toast, mobile hamburger
+ drawer, error boundary, offline banner, loading skeletons, dashboard enrichi.
Documentation: guides utilisateur complets (demarrage, vote, sanctuaire, FAQ 30+),
guide deploiement, politique securite. 123 tests, 155 fichiers.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/app/components/common/ErrorBoundary.vue

@@ -0,0 +1,70 @@
+<script setup lang="ts">
+/**
+ * Error boundary component.
+ *
+ * Wraps slot content with NuxtErrorBoundary and displays a user-friendly
+ * error message in French when child components crash.
+ * Logs error details to console and emits error event for monitoring.
+ */
+
+const emit = defineEmits<{
+  error: [error: any]
+}>()
+
+const hasError = ref(false)
+const errorDetails = ref<string | null>(null)
+
+function handleError(error: any) {
+  hasError.value = true
+  errorDetails.value = error?.message || error?.toString() || 'Erreur inconnue'
+
+  // Log to console for debugging
+  console.error('[ErrorBoundary] Erreur capturee:', error)
+
+  // Emit for external monitoring
+  emit('error', error)
+}
+
+function retry() {
+  hasError.value = false
+  errorDetails.value = null
+}
+</script>
+
+<template>
+  <NuxtErrorBoundary @error="handleError">
+    <template v-if="!hasError">
+      <slot />
+    </template>
+    <template v-else>
+      <div class="flex flex-col items-center justify-center p-8 text-center">
+        <div class="max-w-md space-y-4">
+          <UIcon
+            name="i-lucide-alert-triangle"
+            class="text-5xl text-warning mx-auto"
+          />
+          <h3 class="text-lg font-semibold text-gray-900 dark:text-white">
+            Une erreur est survenue
+          </h3>
+          <p class="text-sm text-gray-600 dark:text-gray-400">
+            Un probleme inattendu s'est produit lors du chargement de ce contenu.
+            Vous pouvez essayer de recharger cette section.
+          </p>
+          <p
+            v-if="errorDetails"
+            class="text-xs text-gray-400 dark:text-gray-500 font-mono bg-gray-100 dark:bg-gray-800 p-2 rounded"
+          >
+            {{ errorDetails }}
+          </p>
+          <UButton
+            icon="i-lucide-refresh-cw"
+            label="Reessayer"
+            color="primary"
+            variant="soft"
+            @click="retry"
+          />
+        </div>
+      </div>
+    </template>
+  </NuxtErrorBoundary>
+</template>