fix(custom-fields) : context fields display, batch save, hierarchy propagation and UniqueEntity fix

- ComponentItem/PieceItem: DaisyUI divider, emit context-field-update for batch save
- CustomFieldDisplay: support editable/emit-blur/title/show-header props
- MachineComponentsCard/MachinePiecesCard: propagate custom-field-update events
- useMachineDetailCustomFields: pendingContextFieldUpdates + saveAllContextCustomFields
- useMachineDetailData: wire context field save into submitEdition
- useMachineDetailUpdates: only PATCH changed machine fields
- useMachineHierarchy: propagate contextCustomFields/Values from link to nodes
- componentStructure: include machineContextOnly in normalizeStructureForEditor
- Machine entity: convert empty reference to null, ignoreNull on UniqueEntity

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

frontend/app/composables/useMachineDetailCustomFields.ts

@@ -44,6 +44,7 @@ export function useMachineDetailCustomFields(deps: MachineDetailCustomFieldsDeps
   // ---------------------------------------------------------------------------
 
   const machineCustomFields = ref<AnyRecord[]>([])
+  const pendingContextFieldUpdates = ref<AnyRecord[]>([])
 
   // ---------------------------------------------------------------------------
   // Computed
@@ -380,6 +381,83 @@ export function useMachineDetailCustomFields(deps: MachineDetailCustomFieldsDeps
     }
   }
 
+  const handleCustomFieldUpdate = async (fieldUpdate: AnyRecord) => {
+    if (fieldUpdate?.entityType && fieldUpdate?.entityId) {
+      queueContextFieldUpdate(fieldUpdate)
+      return
+    }
+
+    await updatePieceCustomField(fieldUpdate)
+  }
+
+  const queueContextFieldUpdate = (fieldUpdate: AnyRecord) => {
+    const entityType = fieldUpdate.entityType as string | undefined
+    const entityId = fieldUpdate.entityId as string | undefined
+    const fieldId = fieldUpdate.fieldId as string | undefined
+    const customFieldValueId = fieldUpdate.customFieldValueId as string | undefined
+
+    if (!entityType || !entityId || (!fieldId && !customFieldValueId)) return
+
+    const nextUpdate = {
+      entityType,
+      entityId,
+      fieldId,
+      customFieldValueId,
+      value: fieldUpdate.value ?? '',
+      fieldName: fieldUpdate.fieldName ?? 'Champ contextuel',
+    }
+
+    const existingIndex = pendingContextFieldUpdates.value.findIndex(
+      (item) =>
+        item.entityType === entityType &&
+        item.entityId === entityId &&
+        item.fieldId === fieldId &&
+        item.customFieldValueId === customFieldValueId,
+    )
+
+    if (existingIndex >= 0) {
+      pendingContextFieldUpdates.value[existingIndex] = nextUpdate
+      return
+    }
+
+    pendingContextFieldUpdates.value.push(nextUpdate)
+  }
+
+  const clearPendingContextFieldUpdates = () => {
+    pendingContextFieldUpdates.value = []
+  }
+
+  const saveAllContextCustomFields = async () => {
+    const updates = pendingContextFieldUpdates.value.slice()
+    if (!updates.length) return
+
+    try {
+      for (const update of updates) {
+        if (update.customFieldValueId) {
+          await updateCustomFieldValueApi(update.customFieldValueId as string, {
+            value: update.value ?? '',
+          } as any)
+          continue
+        }
+
+        if (!update.fieldId) {
+          continue
+        }
+
+        await upsertCustomFieldValue(
+          update.fieldId as string,
+          update.entityType as string,
+          update.entityId as string,
+          update.value ?? '',
+        )
+      }
+      clearPendingContextFieldUpdates()
+    } catch (error) {
+      console.error('Erreur lors de la sauvegarde batch des champs contextuels:', error)
+      throw error
+    }
+  }
+
   const saveAllMachineCustomFields = async () => {
     if (!machine.value) return
 
@@ -435,6 +513,7 @@ export function useMachineDetailCustomFields(deps: MachineDetailCustomFieldsDeps
   return {
     // State
     machineCustomFields,
+    pendingContextFieldUpdates,
 
     // Computed
     visibleMachineCustomFields,
@@ -448,6 +527,10 @@ export function useMachineDetailCustomFields(deps: MachineDetailCustomFieldsDeps
     setMachineCustomFieldValue,
     updateMachineCustomField,
     updatePieceCustomField,
+    handleCustomFieldUpdate,
+    queueContextFieldUpdate,
+    clearPendingContextFieldUpdates,
     saveAllMachineCustomFields,
+    saveAllContextCustomFields,
   }
 }