Restructure Engagement Forgeron + fix GenesisBlock + InertiaSlider

- Seed: restructure Engagement Forgeron (51→59 items) avec 3 nouvelles
  sections: Engagements fondamentaux (EF1-EF3), Engagements techniques
  (ET1-ET3), Qualification (Q0-Q1) liée au protocole Embarquement
- Seed: ajout protocole Embarquement Forgeron (5 jalons: candidature,
  miroir, évaluation, certification Smith, mise en ligne)
- GenesisBlock: fix lisibilité — fond mood-surface teinté accent au lieu
  de mood-text inversé, texte mood-aware au lieu de rgba blanc hardcodé
- InertiaSlider: mini affiche "Inertie" sous le curseur, compact en
  width:fit-content pour s'adapter au label
- Frontend: ajout section qualification dans SECTION_META/SECTION_ORDER
- Pages, composants et tests des sprints précédents

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

frontend/app/pages/documents/[slug].vue

@@ -45,6 +45,9 @@ const SECTION_META: Record<string, { label: string; icon: string }> = {
   introduction: { label: 'Introduction', icon: 'i-lucide-scroll-text' },
   fondamental: { label: 'Engagements fondamentaux', icon: 'i-lucide-shield-check' },
   technique: { label: 'Engagements techniques', icon: 'i-lucide-wrench' },
+  qualification: { label: 'Qualification', icon: 'i-lucide-graduation-cap' },
+  aspirant: { label: 'Aspirant forgeron', icon: 'i-lucide-user-plus' },
+  certificateur: { label: 'Certificateur forgeron', icon: 'i-lucide-stamp' },
   conclusion: { label: 'Conclusion', icon: 'i-lucide-bookmark' },
   annexe: { label: 'Annexes', icon: 'i-lucide-paperclip' },
   formule: { label: 'Formule de vote', icon: 'i-lucide-calculator' },
@@ -52,7 +55,7 @@ const SECTION_META: Record<string, { label: string; icon: string }> = {
   ordonnancement: { label: 'Ordonnancement', icon: 'i-lucide-list-ordered' },
 }
 
-const SECTION_ORDER = ['introduction', 'fondamental', 'technique', 'conclusion', 'annexe', 'formule', 'inertie', 'ordonnancement']
+const SECTION_ORDER = ['introduction', 'fondamental', 'technique', 'qualification', 'aspirant', 'certificateur', 'conclusion', 'annexe', 'formule', 'inertie', 'ordonnancement']
 
 const sections = computed((): Section[] => {
   const grouped: Record<string, DocumentItem[]> = {}
@@ -140,11 +143,36 @@ async function archiveToSanctuary() {
 const activeSection = ref<string | null>(null)
 
 function scrollToSection(tag: string) {
-  const el = document.getElementById(`section-${tag}`)
-  if (el) {
-    el.scrollIntoView({ behavior: 'smooth', block: 'start' })
-    activeSection.value = tag
+  // Expand the section if collapsed
+  if (collapsedSections.value[tag]) {
+    collapsedSections.value[tag] = false
   }
+  nextTick(() => {
+    const el = document.getElementById(`section-${tag}`)
+    if (el) {
+      el.scrollIntoView({ behavior: 'smooth', block: 'start' })
+      activeSection.value = tag
+    }
+  })
+}
+
+// ─── Collapsible sections ────────────────────────────────────
+// First 2 sections open by default, rest collapsed
+
+const collapsedSections = ref<Record<string, boolean>>({})
+
+watch(sections, (newSections) => {
+  if (newSections.length > 0 && Object.keys(collapsedSections.value).length === 0) {
+    const map: Record<string, boolean> = {}
+    newSections.forEach((s, i) => {
+      map[s.tag] = i >= 2 // collapsed if index >= 2
+    })
+    collapsedSections.value = map
+  }
+}, { immediate: true })
+
+function toggleSection(tag: string) {
+  collapsedSections.value[tag] = !collapsedSections.value[tag]
 }
 </script>
 
@@ -280,8 +308,11 @@ function scrollToSection(tag: string) {
           :id="`section-${section.tag}`"
           class="doc-page__section"
         >
-          <!-- Section header -->
-          <div class="doc-page__section-header">
+          <!-- Section header (clickable toggle) -->
+          <button
+            class="doc-page__section-header"
+            @click="toggleSection(section.tag)"
+          >
             <div class="flex items-center gap-2">
               <UIcon :name="section.icon" style="color: var(--mood-accent)" />
               <h2 class="doc-page__section-title">
@@ -291,20 +322,29 @@ function scrollToSection(tag: string) {
                 {{ section.items.length }}
               </UBadge>
             </div>
-            <InertiaSlider :preset="section.inertiaPreset" compact class="max-w-48" />
-          </div>
+            <div class="flex items-center gap-2">
+              <InertiaSlider :preset="section.inertiaPreset" compact mini />
+              <UIcon
+                name="i-lucide-chevron-down"
+                class="doc-page__section-chevron"
+                :class="{ 'doc-page__section-chevron--open': !collapsedSections[section.tag] }"
+              />
+            </div>
+          </button>
 
-          <!-- Items -->
-          <div class="doc-page__section-items">
-            <EngagementCard
-              v-for="item in section.items"
-              :key="item.id"
-              :item="item"
-              :document-slug="slug"
-              :show-actions="auth.isAuthenticated"
-              @propose="handlePropose"
-            />
-          </div>
+          <!-- Items (collapsible) -->
+          <Transition name="section-collapse">
+            <div v-show="!collapsedSections[section.tag]" class="doc-page__section-items">
+              <EngagementCard
+                v-for="item in section.items"
+                :key="item.id"
+                :item="item"
+                :document-slug="slug"
+                :show-actions="auth.isAuthenticated"
+                @propose="handlePropose"
+              />
+            </div>
+          </Transition>
         </div>
       </div>
     </template>
@@ -449,6 +489,27 @@ function scrollToSection(tag: string) {
   gap: 1rem;
   padding: 0.75rem 0;
   border-bottom: 2px solid color-mix(in srgb, var(--mood-accent) 15%, transparent);
+  width: 100%;
+  background: none;
+  cursor: pointer;
+  user-select: none;
+  transition: opacity 0.15s;
+}
+
+.doc-page__section-header:hover {
+  opacity: 0.85;
+}
+
+.doc-page__section-chevron {
+  font-size: 1rem;
+  color: var(--mood-text-muted);
+  transform: rotate(-90deg);
+  transition: transform 0.25s ease;
+  flex-shrink: 0;
+}
+
+.doc-page__section-chevron--open {
+  transform: rotate(0deg);
 }
 
 .doc-page__section-title {
@@ -469,4 +530,22 @@ function scrollToSection(tag: string) {
   flex-direction: column;
   gap: 0.75rem;
 }
+
+/* Section collapse transition */
+.section-collapse-enter-active,
+.section-collapse-leave-active {
+  transition: all 0.3s ease;
+  overflow: hidden;
+}
+
+.section-collapse-enter-from,
+.section-collapse-leave-to {
+  opacity: 0;
+  max-height: 0;
+}
+
+.section-collapse-enter-to,
+.section-collapse-leave-from {
+  opacity: 1;
+}
 </style>