feat(machine) : single save button + link versioning display

- Replace auto-save-on-blur with single "Enregistrer" button
- Add Cancel button that resets local state
- Expose saveFieldDefinitions via defineExpose on MachineInfoCard
- Remove standalone save button from MachineCustomFieldDefEditor
- Add saveAllMachineCustomFields batch method
- Add submitEdition/cancelEdition/saving/canSubmit to orchestrator
- Show diff summary badges in version list entries
- Show link changes in restore modal description

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

app/components/machine/MachineCustomFieldDefEditor.vue

@@ -1,19 +1,8 @@
 <template>
   <section class="space-y-3">
-    <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>
+    <h3 class="text-sm font-semibold">
+      Définitions des champs personnalisés
+    </h3>
 
     <p v-if="!fields.length" class="text-xs text-gray-500">
       Aucun champ personnalisé défini. Cliquez sur « Ajouter » pour en créer un.
@@ -117,7 +106,6 @@ defineProps<{
 }>()
 
 defineEmits<{
-  save: []
   'add-field': []
   'remove-field': [index: number]
 }>()