Sprint 2 : moteur de documents + sanctuaire

Backend:
- CRUD complet documents/items/versions (update, delete, accept, reject, reorder)
- Service IPFS (upload/retrieve/pin via kubo HTTP API)
- Service sanctuaire : pipeline SHA-256 + IPFS + on-chain (system.remark)
- Verification integrite des entrees sanctuaire
- Recherche par reference (document -> entrees sanctuaire)
- Serialisation deterministe des documents pour archivage
- 14 tests unitaires supplementaires (document service)

Frontend:
- 9 composants : StatusBadge, MarkdownRenderer, DiffView, ItemCard,
  ItemVersionDiff, DocumentList, SanctuaryEntry, IPFSLink, ChainAnchor
- Page detail item avec historique des versions et diff
- Page detail sanctuaire avec verification integrite
- Modal de creation de document + proposition de version
- Archivage document vers sanctuaire depuis la page detail

Documentation:
- API reference mise a jour (9 nouveaux endpoints)
- Guides utilisateur documents et sanctuaire enrichis

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

frontend/app/components/documents/ItemVersionDiff.vue

@@ -0,0 +1,95 @@
+<script setup lang="ts">
+import type { ItemVersion } from '~/stores/documents'
+
+const props = defineProps<{
+  version: ItemVersion
+}>()
+
+const emit = defineEmits<{
+  accept: [versionId: string]
+  reject: [versionId: string]
+}>()
+
+const auth = useAuthStore()
+
+function formatDate(dateStr: string): string {
+  return new Date(dateStr).toLocaleDateString('fr-FR', {
+    day: 'numeric',
+    month: 'long',
+    year: 'numeric',
+    hour: '2-digit',
+    minute: '2-digit',
+  })
+}
+
+function truncateAddress(address: string | null): string {
+  if (!address) return 'Inconnu'
+  if (address.length <= 16) return address
+  return address.slice(0, 8) + '...' + address.slice(-6)
+}
+</script>
+
+<template>
+  <UCard>
+    <div class="space-y-4">
+      <!-- Header -->
+      <div class="flex items-start justify-between">
+        <div class="flex items-center gap-3">
+          <CommonStatusBadge :status="version.status" type="version" />
+          <span class="text-sm text-gray-500">
+            Propose par
+            <span class="font-medium text-gray-700 dark:text-gray-300 font-mono text-xs">
+              {{ truncateAddress(version.proposed_by) }}
+            </span>
+          </span>
+        </div>
+        <span class="text-xs text-gray-400">
+          {{ formatDate(version.created_at) }}
+        </span>
+      </div>
+
+      <!-- Rationale -->
+      <div v-if="version.rationale" class="bg-gray-50 dark:bg-gray-800/50 rounded-lg p-3">
+        <p class="text-xs font-semibold text-gray-500 uppercase mb-1">Justification</p>
+        <p class="text-sm text-gray-700 dark:text-gray-300">{{ version.rationale }}</p>
+      </div>
+
+      <!-- Diff view -->
+      <div v-if="version.diff">
+        <p class="text-xs font-semibold text-gray-500 uppercase mb-2">Modifications</p>
+        <CommonDiffView :diff="version.diff" />
+      </div>
+
+      <!-- Proposed text (fallback if no diff) -->
+      <div v-else-if="version.proposed_text">
+        <p class="text-xs font-semibold text-gray-500 uppercase mb-2">Texte propose</p>
+        <div class="bg-green-50 dark:bg-green-900/10 border border-green-200 dark:border-green-800 rounded-lg p-3">
+          <CommonMarkdownRenderer :content="version.proposed_text" />
+        </div>
+      </div>
+
+      <!-- Actions for authenticated users -->
+      <div
+        v-if="auth.isAuthenticated && version.status === 'proposed'"
+        class="flex items-center gap-3 pt-2 border-t border-gray-100 dark:border-gray-800"
+      >
+        <UButton
+          label="Accepter"
+          icon="i-lucide-check"
+          color="success"
+          variant="soft"
+          size="xs"
+          @click="emit('accept', version.id)"
+        />
+        <UButton
+          label="Rejeter"
+          icon="i-lucide-x"
+          color="error"
+          variant="soft"
+          size="xs"
+          @click="emit('reject', version.id)"
+        />
+      </div>
+    </div>
+  </UCard>
+</template>