feat(versioning) : add entity versioning frontend with restore flow

- useEntityVersions composable (list, preview, restore API calls)
- EntityVersionList component with auto-refresh after save
- VersionRestoreModal with context-aware messages per entity type
- Integrate into machine, composant, piece, product detail pages
- Add restore action label to historyDisplayUtils
- Show structure slots in composant/piece consultation mode

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/pages/machine/[id].vue

@@ -71,10 +71,10 @@
         @update:machine-reference="d.machineReference.value = $event"
         @update:machine-site-id="d.machineSiteId.value = $event"
         @update:constructeur-ids="d.handleMachineConstructeurChange"
-        @blur-field="d.updateMachineInfo"
+        @blur-field="() => { d.updateMachineInfo(); refreshVersions() }"
         @set-custom-field-value="d.setMachineCustomFieldValue"
         @update-custom-field="d.updateMachineCustomField"
-        @custom-fields-saved="d.loadMachineData()"
+        @custom-fields-saved="() => { d.loadMachineData(); refreshVersions() }"
       />
 
       <!-- Documents -->
@@ -146,6 +146,17 @@
         :field-labels="historyFieldLabels"
       />
 
+      <!-- Versions -->
+      <EntityVersionList
+        ref="versionListRef"
+        entity-type="machine"
+        :entity-id="String(machineId)"
+        :field-labels="historyFieldLabels"
+        :refresh-key="versionRefreshKey"
+        @restored="d.loadMachineData()"
+
+      />
+
       <!-- Comments -->
       <div class="mt-4">
         <CommentSection
@@ -201,6 +212,7 @@ import MachineComponentsCard from '~/components/machine/MachineComponentsCard.vu
 import MachinePiecesCard from '~/components/machine/MachinePiecesCard.vue'
 import AddEntityToMachineModal from '~/components/machine/AddEntityToMachineModal.vue'
 import EntityHistorySection from '~/components/common/EntityHistorySection.vue'
+import EntityVersionList from '~/components/common/EntityVersionList.vue'
 import IconLucideAlertTriangle from '~icons/lucide/alert-triangle'
 
 const route = useRoute()
@@ -212,6 +224,8 @@ if (!machineId) {
 }
 
 const d = useMachineDetailData(machineId)
+const versionRefreshKey = ref(0)
+const refreshVersions = () => { versionRefreshKey.value++ }
 
 const {
   history,