diff --git a/Inventory_frontend b/Inventory_frontend
index 767c9a7..a741596 160000
--- a/Inventory_frontend
+++ b/Inventory_frontend
@@ -1 +1 @@
-Subproject commit 767c9a7424cdc4f66c6d77fa1377fe93bdfdb837
+Subproject commit a7415964a718bef7c08af6d6399afd778e45b841
diff --git a/docs/superpowers/plans/2026-03-26-machine-single-save.md b/docs/superpowers/plans/2026-03-26-machine-single-save.md
new file mode 100644
index 0000000..7f16058
--- /dev/null
+++ b/docs/superpowers/plans/2026-03-26-machine-single-save.md
@@ -0,0 +1,1074 @@
+# Machine Single Save Button + Link Versioning — Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Replace the machine page's auto-save-on-blur with a single "Enregistrer les modifications" button (matching composant/pièce/produit pages), and add versioning for machine link add/remove operations.
+
+**Architecture:** Frontend changes remove all `@blur` save triggers from MachineInfoCard, consolidate saves into a single `submitEdition()` method in the orchestrator composable, and add Save/Cancel buttons at the bottom of the page. MachineInfoCard exposes `saveFieldDefinitions()` via `defineExpose` so the parent can call it during submit. Backend changes extend `MachineAuditSubscriber`'s `onFlush` to detect link entity insertions/deletions and create audit entries on the parent machine.
+
+**Tech Stack:** Vue 3 / Nuxt 4, Symfony 8, Doctrine ORM, PHP 8.4
+
+---
+
+## File Structure
+
+| Action | File | Responsibility |
+|--------|------|----------------|
+| Modify | `Inventory_frontend/app/components/machine/MachineInfoCard.vue` | Remove blur-triggered saves, expose saveFieldDefinitions via defineExpose |
+| Modify | `Inventory_frontend/app/components/machine/MachineCustomFieldDefEditor.vue` | Remove standalone save button |
+| Modify | `Inventory_frontend/app/pages/machine/[id].vue` | Add Save/Cancel buttons, wire submitEdition via template ref |
+| Modify | `Inventory_frontend/app/composables/useMachineDetailData.ts` | Add submitEdition, cancelEdition, saving, canSubmit |
+| Modify | `Inventory_frontend/app/composables/useMachineDetailUpdates.ts` | Remove auto-save from handleMachineConstructeurChange |
+| Modify | `Inventory_frontend/app/composables/useMachineDetailCustomFields.ts` | Add saveAllMachineCustomFields batch method |
+| Modify | `src/EventSubscriber/MachineAuditSubscriber.php` | Enrich snapshot with links + detect link changes in onFlush |
+
+---
+
+### Task 1: Remove blur-triggered saves from MachineInfoCard
+
+**Files:**
+- Modify: `Inventory_frontend/app/components/machine/MachineInfoCard.vue`
+
+- [ ] **Step 1: Remove `@blur` from name input (line 17)**
+
+Replace:
+```vue
+            @input="$emit('update:machine-name', ($event.target as HTMLInputElement).value)"
+            @blur="$emit('blur-field')"
+```
+With:
+```vue
+            @input="$emit('update:machine-name', ($event.target as HTMLInputElement).value)"
+```
+
+- [ ] **Step 2: Remove `$emit('blur-field')` from site select (line 31)**
+
+Replace:
+```vue
+            @change="$emit('update:machine-site-id', ($event.target as HTMLSelectElement).value); $emit('blur-field')"
+```
+With:
+```vue
+            @change="$emit('update:machine-site-id', ($event.target as HTMLSelectElement).value)"
+```
+
+- [ ] **Step 3: Remove `@blur` from reference input (line 57)**
+
+Replace:
+```vue
+            @input="$emit('update:machine-reference', ($event.target as HTMLInputElement).value)"
+            @blur="$emit('blur-field')"
+```
+With:
+```vue
+            @input="$emit('update:machine-reference', ($event.target as HTMLInputElement).value)"
+```
+
+- [ ] **Step 4: Remove `@blur` from all custom field inputs**
+
+For each custom field input, remove the `@blur="$emit('update-custom-field', field)"` line:
+- text input (line 118)
+- number input (line 127)
+- select (line 135)
+- boolean checkbox (line 152)
+- date input (line 163)
+
+- [ ] **Step 5: Remove `@save` handler from MachineCustomFieldDefEditor usage (line 187)**
+
+Replace:
+```vue
+        <MachineCustomFieldDefEditor
+          :fields="fieldDefs.fields.value"
+          :saving="fieldDefs.saving.value"
+          :reorder-class="fieldDefs.reorderClass"
+          :on-drag-start="fieldDefs.onDragStart"
+          :on-drag-enter="fieldDefs.onDragEnter"
+          :on-drop="fieldDefs.onDrop"
+          :on-drag-end="fieldDefs.onDragEnd"
+          @save="fieldDefs.saveDefinitions()"
+          @add-field="fieldDefs.addField()"
+          @remove-field="fieldDefs.removeField($event)"
+        />
+```
+With:
+```vue
+        <MachineCustomFieldDefEditor
+          :fields="fieldDefs.fields.value"
+          :saving="fieldDefs.saving.value"
+          :reorder-class="fieldDefs.reorderClass"
+          :on-drag-start="fieldDefs.onDragStart"
+          :on-drag-enter="fieldDefs.onDragEnter"
+          :on-drop="fieldDefs.onDrop"
+          :on-drag-end="fieldDefs.onDragEnd"
+          @add-field="fieldDefs.addField()"
+          @remove-field="fieldDefs.removeField($event)"
+        />
+```
+
+- [ ] **Step 6: Remove unused emit declarations and add defineExpose**
+
+Replace the `defineEmits` block (lines 222-231):
+```ts
+const emit = defineEmits<{
+  'update:machine-name': [value: string]
+  'update:machine-reference': [value: string]
+  'update:machine-site-id': [value: string]
+  'update:constructeur-ids': [ids: unknown]
+  'blur-field': []
+  'set-custom-field-value': [field: any, value: unknown]
+  'update-custom-field': [field: any]
+  'custom-fields-saved': []
+}>()
+```
+With:
+```ts
+const emit = defineEmits<{
+  'update:machine-name': [value: string]
+  'update:machine-reference': [value: string]
+  'update:machine-site-id': [value: string]
+  'update:constructeur-ids': [ids: unknown]
+  'set-custom-field-value': [field: any, value: unknown]
+  'custom-fields-saved': []
+}>()
+```
+
+Then, at the end of the `<script setup>` block (after the `watch` at line 239-241), add:
+
+```ts
+defineExpose({
+  saveFieldDefinitions: () => fieldDefs.saveDefinitions(),
+})
+```
+
+- [ ] **Step 7: Commit**
+
+```bash
+git add Inventory_frontend/app/components/machine/MachineInfoCard.vue
+git commit -m "refactor(machine) : remove blur-triggered auto-saves from MachineInfoCard"
+```
+
+---
+
+### Task 2: Remove standalone save button from MachineCustomFieldDefEditor
+
+**Files:**
+- Modify: `Inventory_frontend/app/components/machine/MachineCustomFieldDefEditor.vue`
+
+- [ ] **Step 1: Remove the "Enregistrer les champs" button (lines 7-15)**
+
+Replace the header `div` (lines 3-16):
+```vue
+    <div class="flex items-center justify-between">
+      <h3 class="text-sm font-semibold">
+        Définitions des champs personnalisés
+      </h3>
+      <button
+        type="button"
+        class="btn btn-primary btn-sm"
+        :disabled="saving"
+        @click="$emit('save')"
+      >
+        <span v-if="saving" class="loading loading-spinner loading-xs" />
+        Enregistrer les champs
+      </button>
+    </div>
+```
+With:
+```vue
+    <h3 class="text-sm font-semibold">
+      Définitions des champs personnalisés
+    </h3>
+```
+
+- [ ] **Step 2: Remove the `save` emit from defineEmits (line 120)**
+
+Replace:
+```ts
+defineEmits<{
+  save: []
+  'add-field': []
+  'remove-field': [index: number]
+}>()
+```
+With:
+```ts
+defineEmits<{
+  'add-field': []
+  'remove-field': [index: number]
+}>()
+```
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add Inventory_frontend/app/components/machine/MachineCustomFieldDefEditor.vue
+git commit -m "refactor(machine) : remove standalone save button from custom field def editor"
+```
+
+---
+
+### Task 3: Stop auto-save in handleMachineConstructeurChange
+
+**Files:**
+- Modify: `Inventory_frontend/app/composables/useMachineDetailUpdates.ts:211-214`
+
+- [ ] **Step 1: Remove the auto-save call**
+
+Replace:
+```ts
+  const handleMachineConstructeurChange = async (value: unknown) => {
+    machineConstructeurIds.value = uniqueConstructeurIds(value)
+    await updateMachineInfo()
+  }
+```
+With:
+```ts
+  const handleMachineConstructeurChange = (value: unknown) => {
+    machineConstructeurIds.value = uniqueConstructeurIds(value)
+  }
+```
+
+- [ ] **Step 2: Commit**
+
+```bash
+git add Inventory_frontend/app/composables/useMachineDetailUpdates.ts
+git commit -m "refactor(machine) : stop auto-saving on constructeur change"
+```
+
+---
+
+### Task 4: Add batch custom field save method
+
+**Files:**
+- Modify: `Inventory_frontend/app/composables/useMachineDetailCustomFields.ts`
+
+- [ ] **Step 1: Add `saveAllMachineCustomFields` method**
+
+After the `updatePieceCustomField` method (before the `return` block at line 379), add:
+
+```ts
+  const saveAllMachineCustomFields = async () => {
+    if (!machine.value) return
+
+    const fields = Array.isArray(machineCustomFields.value) ? machineCustomFields.value : []
+    const fieldsToSave = fields.filter(
+      (field) => field.value !== undefined && field.value !== null && String(field.value).trim() !== '',
+    )
+
+    for (const field of fieldsToSave) {
+      const { id: customFieldId, customFieldValueId } = field
+
+      try {
+        if (customFieldValueId) {
+          await updateCustomFieldValueApi(customFieldValueId as string, {
+            value: field.value ?? '',
+          } as any)
+        } else if (customFieldId) {
+          const result: any = await upsertCustomFieldValue(
+            customFieldId as string,
+            'machine',
+            machine.value.id as string,
+            field.value ?? '',
+          )
+          if (result.success) {
+            const createdValue = result.data as AnyRecord
+            if (createdValue?.id) {
+              field.customFieldValueId = createdValue.id
+              if (!createdValue.customField) {
+                createdValue.customField = {
+                  id: customFieldId,
+                  name: field.name,
+                  type: field.type,
+                  required: field.required,
+                  options: field.options,
+                }
+              }
+              const existingValues = Array.isArray(machine.value.customFieldValues)
+                ? (machine.value.customFieldValues as AnyRecord[]).filter(
+                    (item) => item.id !== createdValue.id,
+                  )
+                : []
+              machine.value.customFieldValues = [...existingValues, createdValue]
+            }
+          }
+        }
+      } catch (error) {
+        console.error('Erreur lors de la sauvegarde du champ personnalisé:', error)
+        throw error
+      }
+    }
+  }
+```
+
+- [ ] **Step 2: Export the new method in the return block**
+
+Add `saveAllMachineCustomFields` to the return object:
+
+Replace:
+```ts
+    // Methods
+    syncMachineCustomFields,
+    setMachineCustomFieldValue,
+    updateMachineCustomField,
+    updatePieceCustomField,
+```
+With:
+```ts
+    // Methods
+    syncMachineCustomFields,
+    setMachineCustomFieldValue,
+    updateMachineCustomField,
+    updatePieceCustomField,
+    saveAllMachineCustomFields,
+```
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add Inventory_frontend/app/composables/useMachineDetailCustomFields.ts
+git commit -m "feat(machine) : add batch saveAllMachineCustomFields method"
+```
+
+---
+
+### Task 5: Add submitEdition, cancelEdition, saving, canSubmit to orchestrator
+
+**Files:**
+- Modify: `Inventory_frontend/app/composables/useMachineDetailData.ts`
+
+- [ ] **Step 1: Add `saving` ref in the core state block (after line 63)**
+
+After `const printAreaRef = ref<HTMLElement | null>(null)`, add:
+```ts
+  const saving = ref(false)
+```
+
+- [ ] **Step 2: Destructure `saveAllMachineCustomFields` from custom fields sub-composable (line 145)**
+
+Replace:
+```ts
+    syncMachineCustomFields,
+    setMachineCustomFieldValue,
+    updateMachineCustomField,
+    updatePieceCustomField,
+```
+With:
+```ts
+    syncMachineCustomFields,
+    setMachineCustomFieldValue,
+    updateMachineCustomField,
+    updatePieceCustomField,
+    saveAllMachineCustomFields,
+```
+
+- [ ] **Step 3: Add `canSubmit` computed after the `isEditMode` ref block (after line 111)**
+
+```ts
+  const canSubmit = computed(() => {
+    if (!machine.value) return false
+    if (saving.value) return false
+    if (!machineName.value.trim()) return false
+    return true
+  })
+```
+
+`computed` is already imported from `vue` at line 8.
+
+- [ ] **Step 4: Add `submitEdition` and `cancelEdition` methods after `toggleAllPieces` (after line 303)**
+
+Note: `submitEdition` does NOT call `fieldDefs.saveDefinitions()` directly — the page handles that via a template ref on MachineInfoCard, since `fieldDefs` is instantiated inside MachineInfoCard, not in the orchestrator.
+
+```ts
+  const submitEdition = async () => {
+    if (!machine.value || saving.value) return
+    saving.value = true
+
+    try {
+      // 1. Save machine info (name, reference, site, constructeurs)
+      await updateMachineInfo()
+
+      // 2. Save all custom field values
+      await saveAllMachineCustomFields()
+
+      // 3. Reload machine data to get fresh state
+      await loadMachineData()
+
+      // 4. Exit edit mode
+      isEditMode.value = false
+      toast.showSuccess('Machine mise à jour avec succès')
+    } catch (error) {
+      console.error('Erreur lors de la sauvegarde:', error)
+      toast.showError('Erreur lors de la sauvegarde de la machine')
+    } finally {
+      saving.value = false
+    }
+  }
+
+  const cancelEdition = () => {
+    // Reset local state from machine.value
+    initMachineFields()
+    syncMachineCustomFields()
+    isEditMode.value = false
+  }
+```
+
+- [ ] **Step 5: Expose new items in the return block (line 423+)**
+
+Add to the return object:
+```ts
+    // Save
+    saving, canSubmit, submitEdition, cancelEdition,
+```
+
+- [ ] **Step 6: Commit**
+
+```bash
+git add Inventory_frontend/app/composables/useMachineDetailData.ts
+git commit -m "feat(machine) : add submitEdition, cancelEdition, saving, canSubmit"
+```
+
+---
+
+### Task 6: Wire Save/Cancel buttons in the page
+
+**Files:**
+- Modify: `Inventory_frontend/app/pages/machine/[id].vue`
+
+- [ ] **Step 1: Add template ref on MachineInfoCard (line 56)**
+
+Replace:
+```vue
+      <MachineInfoCard
+```
+With:
+```vue
+      <MachineInfoCard
+        ref="machineInfoCardRef"
+```
+
+- [ ] **Step 2: Remove the blur-field and update-custom-field handlers from MachineInfoCard (lines 73-77)**
+
+Replace:
+```vue
+        @update:constructeur-ids="d.handleMachineConstructeurChange"
+        @blur-field="() => { d.updateMachineInfo(); refreshVersions() }"
+        @set-custom-field-value="d.setMachineCustomFieldValue"
+        @update-custom-field="d.updateMachineCustomField"
+        @custom-fields-saved="() => { d.loadMachineData(); refreshVersions() }"
+```
+With:
+```vue
+        @update:constructeur-ids="d.handleMachineConstructeurChange"
+        @set-custom-field-value="d.setMachineCustomFieldValue"
+        @custom-fields-saved="() => { d.loadMachineData(); refreshVersions() }"
+```
+
+- [ ] **Step 3: Add version refresh to handleAddEntity and link removal handlers**
+
+Replace `handleAddEntity` (lines 253-261):
+```js
+const handleAddEntity = async (entityId) => {
+  if (addModalKind.value === 'component') {
+    await d.addComponentLink(entityId)
+  } else if (addModalKind.value === 'piece') {
+    await d.addPieceLink(entityId)
+  } else {
+    await d.addProductLink(entityId)
+  }
+}
+```
+With:
+```js
+const handleAddEntity = async (entityId) => {
+  if (addModalKind.value === 'component') {
+    await d.addComponentLink(entityId)
+  } else if (addModalKind.value === 'piece') {
+    await d.addPieceLink(entityId)
+  } else {
+    await d.addProductLink(entityId)
+  }
+  refreshVersions()
+}
+```
+
+Replace the three remove link handlers in the template:
+
+MachineProductsCard (line 100):
+```vue
+        @remove-product="d.removeProductLink"
+```
+→
+```vue
+        @remove-product="async (id) => { await d.removeProductLink(id); refreshVersions() }"
+```
+
+MachineComponentsCard (line 115):
+```vue
+        @remove-component="d.removeComponentLink"
+```
+→
+```vue
+        @remove-component="async (id) => { await d.removeComponentLink(id); refreshVersions() }"
+```
+
+MachinePiecesCard (line 129):
+```vue
+        @remove-piece="d.removePieceLink"
+```
+→
+```vue
+        @remove-piece="async (id) => { await d.removePieceLink(id); refreshVersions() }"
+```
+
+- [ ] **Step 4: Add Save/Cancel buttons before EntityHistorySection (before line 141)**
+
+Insert before `<!-- Historique -->`:
+```vue
+      <!-- Save / Cancel buttons -->
+      <div v-if="d.isEditMode.value" class="flex flex-col gap-3 md:flex-row md:justify-end">
+        <button
+          type="button"
+          class="btn btn-ghost"
+          :class="{ 'btn-disabled': d.saving.value }"
+          @click="d.cancelEdition()"
+        >
+          Annuler
+        </button>
+        <button
+          type="button"
+          class="btn btn-primary"
+          :disabled="!d.canSubmit.value"
+          @click="submitMachineEdition"
+        >
+          <span v-if="d.saving.value" class="loading loading-spinner loading-sm mr-2" />
+          Enregistrer les modifications
+        </button>
+      </div>
+```
+
+- [ ] **Step 5: Add ref and submitMachineEdition in the script section**
+
+After `const d = useMachineDetailData(machineId)` (line 226), add:
+```js
+const machineInfoCardRef = ref(null)
+```
+
+After `machineViewTitle` computed (line 265), add:
+```js
+const submitMachineEdition = async () => {
+  // Save field definitions via template ref (fieldDefs lives inside MachineInfoCard)
+  if (machineInfoCardRef.value?.saveFieldDefinitions) {
+    await machineInfoCardRef.value.saveFieldDefinitions()
+  }
+  await d.submitEdition()
+  refreshVersions()
+}
+```
+
+- [ ] **Step 6: Add link versioning labels to historyFieldLabels (lines 237-243)**
+
+Replace:
+```js
+const historyFieldLabels = {
+  name: 'Nom',
+  reference: 'Référence',
+  prix: 'Prix',
+  site: 'Site',
+  constructeurIds: 'Fournisseurs',
+}
+```
+With:
+```js
+const historyFieldLabels = {
+  name: 'Nom',
+  reference: 'Référence',
+  prix: 'Prix',
+  site: 'Site',
+  constructeurIds: 'Fournisseurs',
+  addedComponent: 'Composant ajouté',
+  removedComponent: 'Composant supprimé',
+  addedPiece: 'Pièce ajoutée',
+  removedPiece: 'Pièce supprimée',
+  addedProduct: 'Produit ajouté',
+  removedProduct: 'Produit supprimé',
+}
+```
+
+- [ ] **Step 7: Commit**
+
+```bash
+git add Inventory_frontend/app/pages/machine/[id].vue
+git commit -m "feat(machine) : add single save button and wire cancel/submit"
+```
+
+---
+
+### Task 7: Enrich machine snapshot with link data
+
+**Files:**
+- Modify: `src/EventSubscriber/MachineAuditSubscriber.php`
+
+- [ ] **Step 1: Add link data to snapshotEntity**
+
+Replace the `snapshotEntity` method (lines 37-59):
+```php
+    protected function snapshotEntity(object $entity): array
+    {
+        $customFieldValues = [];
+        foreach ($entity->getCustomFieldValues() as $cfv) {
+            $customFieldValues[] = [
+                'id'        => $cfv->getId(),
+                'fieldName' => $cfv->getCustomField()?->getName(),
+                'fieldId'   => $cfv->getCustomField()?->getId(),
+                'value'     => $cfv->getValue(),
+            ];
+        }
+
+        return [
+            'id'                => $entity->getId(),
+            'name'              => $this->safeGet($entity, 'getName'),
+            'reference'         => $this->safeGet($entity, 'getReference'),
+            'prix'              => $this->safeGet($entity, 'getPrix'),
+            'site'              => $this->normalizeValue($this->safeGet($entity, 'getSite')),
+            'constructeurIds'   => $this->normalizeCollection($entity->getConstructeurs()),
+            'customFieldValues' => $customFieldValues,
+            'version'           => $this->safeGet($entity, 'getVersion'),
+        ];
+    }
+```
+With:
+```php
+    protected function snapshotEntity(object $entity): array
+    {
+        $customFieldValues = [];
+        foreach ($entity->getCustomFieldValues() as $cfv) {
+            $customFieldValues[] = [
+                'id'        => $cfv->getId(),
+                'fieldName' => $cfv->getCustomField()?->getName(),
+                'fieldId'   => $cfv->getCustomField()?->getId(),
+                'value'     => $cfv->getValue(),
+            ];
+        }
+
+        $componentLinks = [];
+        foreach ($entity->getComponentLinks() as $link) {
+            $componentLinks[] = [
+                'id'            => $link->getId(),
+                'composantId'   => $link->getComposant()->getId(),
+                'composantName' => $link->getComposant()->getName(),
+            ];
+        }
+
+        $pieceLinks = [];
+        foreach ($entity->getPieceLinks() as $link) {
+            $pieceLinks[] = [
+                'id'        => $link->getId(),
+                'pieceId'   => $link->getPiece()->getId(),
+                'pieceName' => $link->getPiece()->getName(),
+                'quantity'  => $link->getQuantity(),
+            ];
+        }
+
+        $productLinks = [];
+        foreach ($entity->getProductLinks() as $link) {
+            $productLinks[] = [
+                'id'          => $link->getId(),
+                'productId'   => $link->getProduct()->getId(),
+                'productName' => $link->getProduct()->getName(),
+            ];
+        }
+
+        return [
+            'id'                => $entity->getId(),
+            'name'              => $this->safeGet($entity, 'getName'),
+            'reference'         => $this->safeGet($entity, 'getReference'),
+            'prix'              => $this->safeGet($entity, 'getPrix'),
+            'site'              => $this->normalizeValue($this->safeGet($entity, 'getSite')),
+            'constructeurIds'   => $this->normalizeCollection($entity->getConstructeurs()),
+            'customFieldValues' => $customFieldValues,
+            'componentLinks'    => $componentLinks,
+            'pieceLinks'        => $pieceLinks,
+            'productLinks'      => $productLinks,
+            'version'           => $this->safeGet($entity, 'getVersion'),
+        ];
+    }
+```
+
+- [ ] **Step 2: Run php-cs-fixer**
+
+```bash
+make php-cs-fixer-allow-risky
+```
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add src/EventSubscriber/MachineAuditSubscriber.php
+git commit -m "feat(versioning) : enrich machine snapshot with component/piece/product links"
+```
+
+---
+
+### Task 8: Add link change detection to MachineAuditSubscriber
+
+This uses the existing `onFlush` pattern (same as `collectCustomFieldValueChanges` in `AbstractAuditSubscriber`) instead of a separate subscriber with `postPersist`/`preRemove` — which would cause a `flush()` inside `flush()` anti-pattern.
+
+**Files:**
+- Modify: `src/EventSubscriber/MachineAuditSubscriber.php`
+
+- [ ] **Step 1: Add use statements**
+
+At the top of the file, add:
+```php
+use App\Entity\MachineComponentLink;
+use App\Entity\MachinePieceLink;
+use App\Entity\MachineProductLink;
+use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\UnitOfWork;
+```
+
+- [ ] **Step 2: Override `onFlush` to also collect link changes**
+
+The base `onFlushComplex` in `AbstractAuditSubscriber` already builds `$pendingUpdates`, `$pendingSnapshots`, `$pendingEntities` for collection + custom field changes, then persists audit logs. We need to hook into this.
+
+However, `onFlushComplex` is private in AbstractAuditSubscriber. So we override `onFlush` in `MachineAuditSubscriber` to add link tracking after the parent's processing.
+
+Actually, the simplest correct approach: override the `onFlush` method in `MachineAuditSubscriber` to call `parent::onFlush()` first, then process link entities in a second pass.
+
+But there's a subtlety: after `parent::onFlush()`, the UnitOfWork state may have changed. The cleaner approach is to add a **new protected method** in `AbstractAuditSubscriber` that subclasses can override to inject additional pending changes.
+
+The **simplest approach** that works with the current architecture: Add a new Doctrine listener on `MachineAuditSubscriber` for `postFlush`. After all entities are flushed, check if any link entities were involved, and create a separate audit log.
+
+Actually, let's take an even simpler approach: use a **separate subscriber** that listens to `onFlush` (NOT `postPersist`/`preRemove`), detects link entity insertions/deletions in the UnitOfWork, and creates audit logs for the parent machine within the same flush cycle — exactly how `AbstractAuditSubscriber` does it.
+
+Replace the existing `MachineAuditSubscriber.php` entirely:
+
+```php
+<?php
+
+declare(strict_types=1);
+
+namespace App\EventSubscriber;
+
+use App\Entity\CustomFieldValue;
+use App\Entity\Machine;
+use App\Entity\MachineComponentLink;
+use App\Entity\MachinePieceLink;
+use App\Entity\MachineProductLink;
+use Doctrine\Bundle\DoctrineBundle\Attribute\AsDoctrineListener;
+use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\Events;
+use Doctrine\ORM\Event\OnFlushEventArgs;
+use Doctrine\ORM\UnitOfWork;
+
+#[AsDoctrineListener(event: Events::onFlush)]
+final class MachineAuditSubscriber extends AbstractAuditSubscriber
+{
+    protected function supports(object $entity): bool
+    {
+        return $entity instanceof Machine;
+    }
+
+    protected function entityType(): string
+    {
+        return 'machine';
+    }
+
+    protected function hasCollectionTracking(): bool
+    {
+        return true;
+    }
+
+    protected function getOwnerFromCustomFieldValue(CustomFieldValue $cfv): ?object
+    {
+        $owner = $cfv->getMachine();
+
+        return $owner instanceof Machine ? $owner : null;
+    }
+
+    public function onFlush(OnFlushEventArgs $args): void
+    {
+        // Let parent handle regular Machine entity changes (fields, collections, custom fields)
+        parent::onFlush($args);
+
+        // Now handle link entity changes
+        $em = $args->getObjectManager();
+        if (!$em instanceof EntityManagerInterface) {
+            return;
+        }
+
+        $uow            = $em->getUnitOfWork();
+        $actorProfileId = $this->resolveActorProfileId();
+
+        $this->processLinkChanges($em, $uow, $actorProfileId);
+    }
+
+    private function processLinkChanges(EntityManagerInterface $em, UnitOfWork $uow, ?string $actorProfileId): void
+    {
+        $machineChanges = [];
+
+        // Detect inserted links
+        foreach ($uow->getScheduledEntityInsertions() as $entity) {
+            $info = $this->extractLinkInfo($entity, 'added');
+            if (null === $info) {
+                continue;
+            }
+            $machineId = (string) $info['machine']->getId();
+            if ('' === $machineId) {
+                continue;
+            }
+            $machineChanges[$machineId] ??= ['machine' => $info['machine'], 'diffs' => []];
+            $machineChanges[$machineId]['diffs'][$info['diffKey']] = [
+                'from' => null,
+                'to'   => $info['diffValue'],
+            ];
+        }
+
+        // Detect deleted links
+        foreach ($uow->getScheduledEntityDeletions() as $entity) {
+            $info = $this->extractLinkInfo($entity, 'removed');
+            if (null === $info) {
+                continue;
+            }
+            $machineId = (string) $info['machine']->getId();
+            if ('' === $machineId) {
+                continue;
+            }
+            $machineChanges[$machineId] ??= ['machine' => $info['machine'], 'diffs' => []];
+            $machineChanges[$machineId]['diffs'][$info['diffKey']] = [
+                'from' => $info['diffValue'],
+                'to'   => null,
+            ];
+        }
+
+        // Create audit logs for each affected machine
+        foreach ($machineChanges as $machineId => $change) {
+            $machine = $change['machine'];
+            $diff    = $change['diffs'];
+
+            if ([] === $diff) {
+                continue;
+            }
+
+            $version  = $this->incrementEntityVersion($machine, $em, $uow);
+            $snapshot = $this->snapshotEntity($machine);
+
+            $this->persistAuditLog(
+                $em,
+                new \App\Entity\AuditLog('machine', $machineId, 'update', $diff, $snapshot, $actorProfileId, $version),
+            );
+        }
+    }
+
+    /**
+     * @return array{machine: Machine, diffKey: string, diffValue: array{id: string, name: string}}|null
+     */
+    private function extractLinkInfo(object $entity, string $action): ?array
+    {
+        if ($entity instanceof MachineComponentLink) {
+            return [
+                'machine'   => $entity->getMachine(),
+                'diffKey'   => $action . 'Component',
+                'diffValue' => [
+                    'id'   => $entity->getComposant()->getId(),
+                    'name' => $entity->getComposant()->getName(),
+                ],
+            ];
+        }
+
+        if ($entity instanceof MachinePieceLink) {
+            return [
+                'machine'   => $entity->getMachine(),
+                'diffKey'   => $action . 'Piece',
+                'diffValue' => [
+                    'id'   => $entity->getPiece()->getId(),
+                    'name' => $entity->getPiece()->getName(),
+                ],
+            ];
+        }
+
+        if ($entity instanceof MachineProductLink) {
+            return [
+                'machine'   => $entity->getMachine(),
+                'diffKey'   => $action . 'Product',
+                'diffValue' => [
+                    'id'   => $entity->getProduct()->getId(),
+                    'name' => $entity->getProduct()->getName(),
+                ],
+            ];
+        }
+
+        return null;
+    }
+
+    protected function snapshotEntity(object $entity): array
+    {
+        $customFieldValues = [];
+        foreach ($entity->getCustomFieldValues() as $cfv) {
+            $customFieldValues[] = [
+                'id'        => $cfv->getId(),
+                'fieldName' => $cfv->getCustomField()?->getName(),
+                'fieldId'   => $cfv->getCustomField()?->getId(),
+                'value'     => $cfv->getValue(),
+            ];
+        }
+
+        $componentLinks = [];
+        foreach ($entity->getComponentLinks() as $link) {
+            $componentLinks[] = [
+                'id'            => $link->getId(),
+                'composantId'   => $link->getComposant()->getId(),
+                'composantName' => $link->getComposant()->getName(),
+            ];
+        }
+
+        $pieceLinks = [];
+        foreach ($entity->getPieceLinks() as $link) {
+            $pieceLinks[] = [
+                'id'        => $link->getId(),
+                'pieceId'   => $link->getPiece()->getId(),
+                'pieceName' => $link->getPiece()->getName(),
+                'quantity'  => $link->getQuantity(),
+            ];
+        }
+
+        $productLinks = [];
+        foreach ($entity->getProductLinks() as $link) {
+            $productLinks[] = [
+                'id'          => $link->getId(),
+                'productId'   => $link->getProduct()->getId(),
+                'productName' => $link->getProduct()->getName(),
+            ];
+        }
+
+        return [
+            'id'                => $entity->getId(),
+            'name'              => $this->safeGet($entity, 'getName'),
+            'reference'         => $this->safeGet($entity, 'getReference'),
+            'prix'              => $this->safeGet($entity, 'getPrix'),
+            'site'              => $this->normalizeValue($this->safeGet($entity, 'getSite')),
+            'constructeurIds'   => $this->normalizeCollection($entity->getConstructeurs()),
+            'customFieldValues' => $customFieldValues,
+            'componentLinks'    => $componentLinks,
+            'pieceLinks'        => $pieceLinks,
+            'productLinks'      => $productLinks,
+            'version'           => $this->safeGet($entity, 'getVersion'),
+        ];
+    }
+}
+```
+
+Note: This combines Task 7 (snapshot enrichment) into this file. If you already committed Task 7 separately, this replaces the full file content.
+
+- [ ] **Step 2: Run php-cs-fixer**
+
+```bash
+make php-cs-fixer-allow-risky
+```
+
+- [ ] **Step 3: Run tests**
+
+```bash
+make test
+```
+
+- [ ] **Step 4: Commit**
+
+```bash
+git add src/EventSubscriber/MachineAuditSubscriber.php
+git commit -m "feat(versioning) : detect machine link add/remove in onFlush and create audit logs"
+```
+
+---
+
+### Task 9: Frontend lint and typecheck
+
+**Files:** All modified frontend files
+
+- [ ] **Step 1: Run ESLint fix**
+
+```bash
+cd Inventory_frontend && npm run lint:fix
+```
+
+- [ ] **Step 2: Run typecheck**
+
+```bash
+cd Inventory_frontend && npx nuxi typecheck
+```
+
+Expected: 0 errors.
+
+- [ ] **Step 3: Fix any issues found and commit**
+
+```bash
+git add -A && git commit -m "fix(machine) : fix lint and type issues from single save refactor"
+```
+
+---
+
+### Task 10: Backend lint and test
+
+**Files:** All modified backend files
+
+- [ ] **Step 1: Run php-cs-fixer**
+
+```bash
+make php-cs-fixer-allow-risky
+```
+
+- [ ] **Step 2: Run tests**
+
+```bash
+make test
+```
+
+Expected: All tests pass.
+
+- [ ] **Step 3: Fix any issues and commit**
+
+```bash
+git add -A && git commit -m "fix(machine) : fix cs-fixer and test issues from single save refactor"
+```
+
+---
+
+### Task 11: Manual verification
+
+- [ ] **Step 1: Start the app**
+
+```bash
+make start
+cd Inventory_frontend && npm run dev
+```
+
+- [ ] **Step 2: Test single save flow**
+
+1. Navigate to a machine detail page
+2. Click edit
+3. Change name, reference, site, constructeurs, custom field values, custom field definitions
+4. Verify NO API calls are fired while editing (check network tab)
+5. Click "Enregistrer les modifications"
+6. Verify batch of API calls fires (machine info + custom fields + field defs)
+7. Verify page reloads in view mode with updated values
+8. Verify new version appears in version list
+
+- [ ] **Step 3: Test cancel flow**
+
+1. Edit a machine, make changes to all fields
+2. Click "Annuler"
+3. Verify all fields reset to original values
+4. Verify no API calls were made
+
+- [ ] **Step 4: Test link versioning**
+
+1. Add a composant to a machine via modal
+2. Check the versions section — should show new version with "Composant ajouté"
+3. Remove a pièce — should show "Pièce supprimée"
+4. Add/remove a produit — same pattern
+
+- [ ] **Step 5: Test documents still work**
+
+1. Upload a document — should save immediately
+2. Delete a document — should delete immediately
+3. No change in behavior
diff --git a/docs/superpowers/specs/2026-03-26-machine-single-save-design.md b/docs/superpowers/specs/2026-03-26-machine-single-save-design.md
new file mode 100644
index 0000000..dc3a658
--- /dev/null
+++ b/docs/superpowers/specs/2026-03-26-machine-single-save-design.md
@@ -0,0 +1,117 @@
+# Machine : Bouton Save Unique + Versioning des Liens
+
+**Date :** 2026-03-26
+**Statut :** Approuvé
+
+## Contexte
+
+La page machine utilise actuellement un auto-save au blur pour chaque champ (info, custom fields, constructeurs). Les pages composant/pièce/produit utilisent un bouton unique "Enregistrer les modifications" en bas du formulaire. L'objectif est d'aligner la page machine sur ce pattern.
+
+De plus, les ajouts/suppressions de liens composant/pièce/produit sur une machine ne sont pas tracés dans le versioning. Ils doivent l'être.
+
+## Volet 1 : Bouton Save Unique
+
+### Comportement cible
+
+- En mode édition, tous les champs (info machine, custom field values, custom field definitions, constructeurs) sont modifiés localement sans appel API.
+- Un bouton "Enregistrer les modifications" en bas du formulaire sauvegarde tout d'un coup.
+- Un bouton "Annuler" réinitialise l'état local et sort du mode édition.
+- Les documents restent en upload/suppression immédiate (inchangé).
+- Les ajouts/suppressions de liens composant/pièce/produit restent immédiats via modales (inchangé).
+
+### Changements frontend
+
+#### MachineInfoCard.vue
+- Supprimer les `@blur` → `$emit('blur-field')` sur les inputs (nom, référence)
+- Supprimer le `@change` qui émet `blur-field` sur le select site
+- Supprimer les `@blur` → `$emit('update-custom-field', field)` sur tous les champs custom
+- Conserver `@input` / `@update:*` / `set-custom-field-value` pour la mise à jour de l'état local
+- Le `MachineCustomFieldDefEditor` perd son bouton save propre : l'état est collecté au submit global
+
+#### machine/[id].vue
+- Supprimer le handler `@blur-field`
+- Supprimer le handler `@update-custom-field`
+- `@update:constructeur-ids` met à jour l'état local sans save
+- Ajouter le bloc boutons en bas (pattern identique à component/[id]/index.vue) :
+  - "Annuler" (btn-ghost) → `cancelEdition()` : réinitialise depuis `machine.value` + sort du mode édition
+  - "Enregistrer les modifications" (btn-primary, disabled si `!canSubmit`) → `submitEdition()`
+
+#### useMachineDetailData.ts
+- Exposer `saving` ref
+- Exposer `submitEdition()` :
+  1. `updateMachineInfo()` — PATCH machine (nom, ref, site, constructeurs)
+  2. Batch save custom field values (tous les `visibleMachineCustomFields` avec valeur)
+  3. Save custom field definitions si modifiées (`fieldDefs.saveDefinitions()`)
+  4. `loadMachineData()` pour recharger
+  5. Sortie du mode édition + toast succès
+- Exposer `cancelEdition()` :
+  1. `initMachineFields()` — réinitialise nom, ref, site, constructeurs depuis `machine.value`
+  2. `syncMachineCustomFields()` — réinitialise les custom fields
+  3. Sort du mode édition
+
+#### useMachineDetailUpdates.ts
+- `handleMachineConstructeurChange` ne déclenche plus `updateMachineInfo()`, met juste à jour le ref local
+
+#### useMachineDetailCustomFields.ts
+- `updateMachineCustomField` n'est plus appelé au blur — sera appelé en batch par `submitEdition()`
+- Ajouter méthode `saveAllMachineCustomFields()` qui itère sur les champs visibles et sauvegarde ceux avec valeur
+
+### Validation (`canSubmit`)
+- Machine existe
+- Nom non vide
+- Pas en cours de sauvegarde (`!saving.value`)
+- `canEdit` est true
+
+## Volet 2 : Versioning des Liens Machine
+
+### Comportement cible
+
+Quand un composant, pièce ou produit est ajouté ou supprimé d'une machine, cela doit :
+1. Incrémenter la `version` de la Machine
+2. Créer une entrée `AuditLog` avec diff et snapshot
+
+### Changements backend
+
+#### MachineAuditSubscriber — enrichir le snapshot
+Ajouter au snapshot machine les liens :
+```php
+'componentLinks' => array_map(fn($link) => [
+    'id' => $link->getId(),
+    'composantId' => $link->getComposant()->getId(),
+    'composantName' => $link->getComposant()->getName(),
+], $entity->getComponentLinks()->toArray()),
+'pieceLinks' => [...],
+'productLinks' => [...],
+```
+
+#### Nouveau subscriber ou service : MachineLinkAuditService
+Écouter les événements Doctrine `postPersist` et `postRemove` sur les 3 entités link.
+Quand un lien est créé/supprimé :
+1. Récupérer la Machine parente
+2. Incrémenter `$machine->incrementVersion()`
+3. Créer un `AuditLog` :
+   - `entityType: 'machine'`
+   - `entityId: $machine->getId()`
+   - `action: 'update'`
+   - `diff: { addedComponent: {id, name} }` ou `{ removedPiece: {id, name} }`
+   - `snapshot:` snapshot complet de la machine (avec liens mis à jour)
+   - `version:` nouvelle version
+
+### Labels pour le diff (frontend)
+Ajouter au `historyFieldLabels` de la page machine :
+```js
+addedComponent: 'Composant ajouté',
+removedComponent: 'Composant supprimé',
+addedPiece: 'Pièce ajoutée',
+removedPiece: 'Pièce supprimée',
+addedProduct: 'Produit ajouté',
+removedProduct: 'Produit supprimé',
+```
+
+## Ce qui ne change PAS
+
+- Upload/suppression de documents (immédiat)
+- Pattern read/edit toggle dans le header
+- L'affichage des sections composants/pièces/produits
+- Les modales d'ajout/suppression de liens (restent immédiates)
+- Le versioning des autres entités (composant, pièce, produit)
diff --git a/migrations/Version20260326120000.php b/migrations/Version20260326120000.php
new file mode 100644
index 0000000..08ec1cc
--- /dev/null
+++ b/migrations/Version20260326120000.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20260326120000 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add referenceFormula and requiredFieldsForReference to model_types, referenceAuto to pieces';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE model_types ADD COLUMN IF NOT EXISTS referenceformula TEXT DEFAULT NULL');
+        $this->addSql('ALTER TABLE model_types ADD COLUMN IF NOT EXISTS requiredfieldsforreference JSON DEFAULT NULL');
+        $this->addSql('ALTER TABLE pieces ADD COLUMN IF NOT EXISTS referenceauto VARCHAR(255) DEFAULT NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE pieces DROP COLUMN IF EXISTS referenceauto');
+        $this->addSql('ALTER TABLE model_types DROP COLUMN IF EXISTS requiredfieldsforreference');
+        $this->addSql('ALTER TABLE model_types DROP COLUMN IF EXISTS referenceformula');
+    }
+}
diff --git a/src/EventSubscriber/MachineAuditSubscriber.php b/src/EventSubscriber/MachineAuditSubscriber.php
index de89960..1fea89c 100644
--- a/src/EventSubscriber/MachineAuditSubscriber.php
+++ b/src/EventSubscriber/MachineAuditSubscriber.php
@@ -4,14 +4,38 @@ declare(strict_types=1);
 
 namespace App\EventSubscriber;
 
+use App\Entity\AuditLog;
 use App\Entity\CustomFieldValue;
 use App\Entity\Machine;
+use App\Entity\MachineComponentLink;
+use App\Entity\MachinePieceLink;
+use App\Entity\MachineProductLink;
 use Doctrine\Bundle\DoctrineBundle\Attribute\AsDoctrineListener;
+use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\Event\OnFlushEventArgs;
 use Doctrine\ORM\Events;
+use Doctrine\ORM\UnitOfWork;
 
 #[AsDoctrineListener(event: Events::onFlush)]
 final class MachineAuditSubscriber extends AbstractAuditSubscriber
 {
+    public function onFlush(OnFlushEventArgs $args): void
+    {
+        // Let parent handle regular Machine entity changes (fields, collections, custom fields)
+        parent::onFlush($args);
+
+        // Now handle link entity changes
+        $em = $args->getObjectManager();
+        if (!$em instanceof EntityManagerInterface) {
+            return;
+        }
+
+        $uow            = $em->getUnitOfWork();
+        $actorProfileId = $this->resolveActorProfileId();
+
+        $this->processLinkChanges($em, $uow, $actorProfileId);
+    }
+
     protected function supports(object $entity): bool
     {
         return $entity instanceof Machine;
@@ -46,6 +70,34 @@ final class MachineAuditSubscriber extends AbstractAuditSubscriber
             ];
         }
 
+        $componentLinks = [];
+        foreach ($entity->getComponentLinks() as $link) {
+            $componentLinks[] = [
+                'id'            => $link->getId(),
+                'composantId'   => $link->getComposant()->getId(),
+                'composantName' => $link->getComposant()->getName(),
+            ];
+        }
+
+        $pieceLinks = [];
+        foreach ($entity->getPieceLinks() as $link) {
+            $pieceLinks[] = [
+                'id'        => $link->getId(),
+                'pieceId'   => $link->getPiece()->getId(),
+                'pieceName' => $link->getPiece()->getName(),
+                'quantity'  => $link->getQuantity(),
+            ];
+        }
+
+        $productLinks = [];
+        foreach ($entity->getProductLinks() as $link) {
+            $productLinks[] = [
+                'id'          => $link->getId(),
+                'productId'   => $link->getProduct()->getId(),
+                'productName' => $link->getProduct()->getName(),
+            ];
+        }
+
         return [
             'id'                => $entity->getId(),
             'name'              => $this->safeGet($entity, 'getName'),
@@ -54,7 +106,108 @@ final class MachineAuditSubscriber extends AbstractAuditSubscriber
             'site'              => $this->normalizeValue($this->safeGet($entity, 'getSite')),
             'constructeurIds'   => $this->normalizeCollection($entity->getConstructeurs()),
             'customFieldValues' => $customFieldValues,
+            'componentLinks'    => $componentLinks,
+            'pieceLinks'        => $pieceLinks,
+            'productLinks'      => $productLinks,
             'version'           => $this->safeGet($entity, 'getVersion'),
         ];
     }
+
+    private function processLinkChanges(EntityManagerInterface $em, UnitOfWork $uow, ?string $actorProfileId): void
+    {
+        $machineChanges = [];
+
+        // Detect inserted links
+        foreach ($uow->getScheduledEntityInsertions() as $entity) {
+            $info = $this->extractLinkInfo($entity, 'added');
+            if (null === $info) {
+                continue;
+            }
+            $machineId = (string) $info['machine']->getId();
+            if ('' === $machineId) {
+                continue;
+            }
+            $machineChanges[$machineId] ??= ['machine' => $info['machine'], 'diffs' => []];
+            $machineChanges[$machineId]['diffs'][$info['diffKey']] = [
+                'from' => null,
+                'to'   => $info['diffValue'],
+            ];
+        }
+
+        // Detect deleted links
+        foreach ($uow->getScheduledEntityDeletions() as $entity) {
+            $info = $this->extractLinkInfo($entity, 'removed');
+            if (null === $info) {
+                continue;
+            }
+            $machineId = (string) $info['machine']->getId();
+            if ('' === $machineId) {
+                continue;
+            }
+            $machineChanges[$machineId] ??= ['machine' => $info['machine'], 'diffs' => []];
+            $machineChanges[$machineId]['diffs'][$info['diffKey']] = [
+                'from' => $info['diffValue'],
+                'to'   => null,
+            ];
+        }
+
+        // Create audit logs for each affected machine
+        foreach ($machineChanges as $machineId => $change) {
+            $machine = $change['machine'];
+            $diff    = $change['diffs'];
+
+            if ([] === $diff) {
+                continue;
+            }
+
+            $version  = $this->incrementEntityVersion($machine, $em, $uow);
+            $snapshot = $this->snapshotEntity($machine);
+
+            $this->persistAuditLog(
+                $em,
+                new AuditLog('machine', $machineId, 'update', $diff, $snapshot, $actorProfileId, $version),
+            );
+        }
+    }
+
+    /**
+     * @return null|array{machine: Machine, diffKey: string, diffValue: array{id: string, name: string}}
+     */
+    private function extractLinkInfo(object $entity, string $action): ?array
+    {
+        if ($entity instanceof MachineComponentLink) {
+            return [
+                'machine'   => $entity->getMachine(),
+                'diffKey'   => $action.'Component',
+                'diffValue' => [
+                    'id'   => $entity->getComposant()->getId(),
+                    'name' => $entity->getComposant()->getName(),
+                ],
+            ];
+        }
+
+        if ($entity instanceof MachinePieceLink) {
+            return [
+                'machine'   => $entity->getMachine(),
+                'diffKey'   => $action.'Piece',
+                'diffValue' => [
+                    'id'   => $entity->getPiece()->getId(),
+                    'name' => $entity->getPiece()->getName(),
+                ],
+            ];
+        }
+
+        if ($entity instanceof MachineProductLink) {
+            return [
+                'machine'   => $entity->getMachine(),
+                'diffKey'   => $action.'Product',
+                'diffValue' => [
+                    'id'   => $entity->getProduct()->getId(),
+                    'name' => $entity->getProduct()->getName(),
+                ],
+            ];
+        }
+
+        return null;
+    }
 }
diff --git a/src/Service/EntityVersionService.php b/src/Service/EntityVersionService.php
index c794be7..d12229e 100644
--- a/src/Service/EntityVersionService.php
+++ b/src/Service/EntityVersionService.php
@@ -10,6 +10,9 @@ use App\Entity\ComposantPieceSlot;
 use App\Entity\ComposantProductSlot;
 use App\Entity\ComposantSubcomponentSlot;
 use App\Entity\Machine;
+use App\Entity\MachineComponentLink;
+use App\Entity\MachinePieceLink;
+use App\Entity\MachineProductLink;
 use App\Entity\Piece;
 use App\Entity\PieceProductSlot;
 use App\Entity\Product;
@@ -295,6 +298,40 @@ final class EntityVersionService
             return $warnings;
         }
 
+        // Machine: check link references
+        if ('machine' === $entityType) {
+            $linkChecks = [
+                ['key' => 'componentLinks', 'refKey' => 'composantId', 'nameKey' => 'composantName', 'label' => 'composant', 'repo' => $this->composants],
+                ['key' => 'pieceLinks', 'refKey' => 'pieceId', 'nameKey' => 'pieceName', 'label' => 'pièce', 'repo' => $this->pieces],
+                ['key' => 'productLinks', 'refKey' => 'productId', 'nameKey' => 'productName', 'label' => 'produit', 'repo' => $this->products],
+            ];
+
+            foreach ($linkChecks as $check) {
+                $links  = $snapshot[$check['key']] ?? [];
+                $refIds = [];
+                foreach ($links as $link) {
+                    $refId = $link[$check['refKey']] ?? null;
+                    if (null !== $refId) {
+                        $refIds[$refId] = $link[$check['nameKey']] ?? $refId;
+                    }
+                }
+                if ([] === $refIds) {
+                    continue;
+                }
+                $foundIds = array_map(fn ($e) => $e->getId(), $check['repo']->findBy(['id' => array_keys($refIds)]));
+                foreach ($refIds as $id => $name) {
+                    if (!in_array($id, $foundIds, true)) {
+                        $warnings[] = [
+                            'field'             => $check['key'],
+                            'message'           => sprintf("Le %s '%s' n'existe plus. Le lien ne sera pas restauré.", $check['label'], $name),
+                            'missingEntityId'   => $id,
+                            'missingEntityName' => $name,
+                        ];
+                    }
+                }
+            }
+        }
+
         // Full mode: check slot references (batch queries per slot type)
         $slotChecks = match ($entityType) {
             'composant' => [
@@ -385,6 +422,48 @@ final class EntityVersionService
                 }
             }
 
+            // Machine: link diffs
+            if ('machine' === $entityType) {
+                $linkTypes = [
+                    'componentLinks' => ['idKey' => 'composantId', 'nameKey' => 'composantName', 'getter' => 'getComponentLinks', 'entityGetter' => 'getComposant'],
+                    'pieceLinks'     => ['idKey' => 'pieceId', 'nameKey' => 'pieceName', 'getter' => 'getPieceLinks', 'entityGetter' => 'getPiece'],
+                    'productLinks'   => ['idKey' => 'productId', 'nameKey' => 'productName', 'getter' => 'getProductLinks', 'entityGetter' => 'getProduct'],
+                ];
+
+                foreach ($linkTypes as $key => $config) {
+                    $currentIds   = [];
+                    $currentNames = [];
+                    if (method_exists($entity, $config['getter'])) {
+                        foreach ($entity->{$config['getter']}() as $link) {
+                            $linked                         = $link->{$config['entityGetter']}();
+                            $currentIds[]                   = $linked->getId();
+                            $currentNames[$linked->getId()] = $linked->getName();
+                        }
+                    }
+
+                    $snapshotIds   = [];
+                    $snapshotNames = [];
+                    foreach ($snapshot[$key] ?? [] as $entry) {
+                        $id = $entry[$config['idKey']] ?? null;
+                        if ($id) {
+                            $snapshotIds[]      = $id;
+                            $snapshotNames[$id] = $entry[$config['nameKey']] ?? $id;
+                        }
+                    }
+
+                    sort($currentIds);
+                    sort($snapshotIds);
+                    if ($currentIds !== $snapshotIds) {
+                        $currentDisplay  = array_map(fn ($id) => $currentNames[$id] ?? $id, $currentIds);
+                        $restoredDisplay = array_map(fn ($id) => $snapshotNames[$id] ?? $id, $snapshotIds);
+                        $diff[$key]      = [
+                            'current'  => [] !== $currentDisplay ? implode(', ', $currentDisplay) : '(aucun)',
+                            'restored' => [] !== $restoredDisplay ? implode(', ', $restoredDisplay) : '(aucun)',
+                        ];
+                    }
+                }
+            }
+
             // Custom field values diff
             $snapshotCfvs = $snapshot['customFieldValues'] ?? [];
             if ([] !== $snapshotCfvs && method_exists($entity, 'getCustomFieldValues')) {
@@ -453,6 +532,11 @@ final class EntityVersionService
             default     => null,
         };
 
+        // Machine: restore links
+        if ('machine' === $entityType) {
+            $this->restoreMachineLinks($entity, $snapshot);
+        }
+
         // Full mode: restore custom field values
         $this->restoreCustomFieldValues($entityType, $entity, $snapshot);
     }
@@ -490,6 +574,62 @@ final class EntityVersionService
         }
     }
 
+    private function restoreMachineLinks(Machine $machine, array $snapshot): void
+    {
+        // Remove all existing links
+        foreach ($machine->getProductLinks()->toArray() as $link) {
+            $this->em->remove($link);
+        }
+        foreach ($machine->getPieceLinks()->toArray() as $link) {
+            $this->em->remove($link);
+        }
+        foreach ($machine->getComponentLinks()->toArray() as $link) {
+            $this->em->remove($link);
+        }
+
+        // Flush removals to avoid FK conflicts
+        $this->em->flush();
+
+        // Recreate component links
+        foreach ($snapshot['componentLinks'] ?? [] as $data) {
+            $composant = !empty($data['composantId']) ? $this->composants->find($data['composantId']) : null;
+            if (null === $composant) {
+                continue;
+            }
+            $link = new MachineComponentLink();
+            $link->setMachine($machine);
+            $link->setComposant($composant);
+            $this->em->persist($link);
+        }
+
+        // Recreate piece links
+        foreach ($snapshot['pieceLinks'] ?? [] as $data) {
+            $piece = !empty($data['pieceId']) ? $this->pieces->find($data['pieceId']) : null;
+            if (null === $piece) {
+                continue;
+            }
+            $link = new MachinePieceLink();
+            $link->setMachine($machine);
+            $link->setPiece($piece);
+            if (isset($data['quantity']) && $data['quantity'] > 0) {
+                $link->setQuantity((int) $data['quantity']);
+            }
+            $this->em->persist($link);
+        }
+
+        // Recreate product links
+        foreach ($snapshot['productLinks'] ?? [] as $data) {
+            $product = !empty($data['productId']) ? $this->products->find($data['productId']) : null;
+            if (null === $product) {
+                continue;
+            }
+            $link = new MachineProductLink();
+            $link->setMachine($machine);
+            $link->setProduct($product);
+            $this->em->persist($link);
+        }
+    }
+
     private function restoreComposantSlots(Composant $entity, array $snapshot): void
     {
         // Clear existing slots
@@ -672,6 +812,31 @@ final class EntityVersionService
             $snapshot['site'] = $site ? ['id' => $site->getId(), 'name' => $site->getName()] : null;
         }
 
+        // Machine: links
+        if ('machine' === $entityType) {
+            $snapshot['componentLinks'] = [];
+            foreach ($entity->getComponentLinks() as $link) {
+                $snapshot['componentLinks'][] = [
+                    'id'            => $link->getId(), 'composantId' => $link->getComposant()->getId(),
+                    'composantName' => $link->getComposant()->getName(),
+                ];
+            }
+            $snapshot['pieceLinks'] = [];
+            foreach ($entity->getPieceLinks() as $link) {
+                $snapshot['pieceLinks'][] = [
+                    'id'        => $link->getId(), 'pieceId' => $link->getPiece()->getId(),
+                    'pieceName' => $link->getPiece()->getName(), 'quantity' => $link->getQuantity(),
+                ];
+            }
+            $snapshot['productLinks'] = [];
+            foreach ($entity->getProductLinks() as $link) {
+                $snapshot['productLinks'][] = [
+                    'id'          => $link->getId(), 'productId' => $link->getProduct()->getId(),
+                    'productName' => $link->getProduct()->getName(),
+                ];
+            }
+        }
+
         // Composant/Piece: product
         if (in_array($entityType, ['composant', 'piece'], true) && method_exists($entity, 'getProduct')) {
             $product             = $entity->getProduct();