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/common/MarkdownRenderer.vue

@@ -0,0 +1,67 @@
+<script setup lang="ts">
+const props = defineProps<{
+  content: string
+}>()
+
+/**
+ * Basic markdown rendering: bold, line breaks, unordered lists.
+ * Returns sanitized HTML string for v-html usage.
+ */
+const renderedHtml = computed(() => {
+  if (!props.content) return ''
+
+  let html = props.content
+
+  // Escape HTML entities to prevent XSS
+  html = html
+    .replace(/&/g, '&amp;')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+
+  // Convert **bold** to <strong>
+  html = html.replace(/\*\*(.+?)\*\*/g, '<strong>$1</strong>')
+
+  // Convert *italic* to <em>
+  html = html.replace(/\*(.+?)\*/g, '<em>$1</em>')
+
+  // Process lines for list items
+  const lines = html.split('\n')
+  const result: string[] = []
+  let inList = false
+
+  for (const line of lines) {
+    const trimmed = line.trim()
+
+    if (trimmed.startsWith('- ')) {
+      if (!inList) {
+        result.push('<ul class="list-disc list-inside space-y-1 my-2">')
+        inList = true
+      }
+      result.push(`<li>${trimmed.slice(2)}</li>`)
+    } else {
+      if (inList) {
+        result.push('</ul>')
+        inList = false
+      }
+      if (trimmed === '') {
+        result.push('<br>')
+      } else {
+        result.push(`<p class="my-1">${line}</p>`)
+      }
+    }
+  }
+
+  if (inList) {
+    result.push('</ul>')
+  }
+
+  return result.join('\n')
+})
+</script>
+
+<template>
+  <div
+    class="prose prose-sm dark:prose-invert max-w-none text-gray-700 dark:text-gray-300 leading-relaxed"
+    v-html="renderedHtml"
+  />
+</template>