fix(machine-detail) : hide empty sections in consultation mode

Documents, products, components and pieces cards are now hidden when
empty in consultation mode. They remain visible in edit mode so users
can still add items. Addresses Geoffrey's feedback (INV-7).

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

app/pages/machine/[id].vue

@@ -79,6 +79,7 @@
 
       <!-- Documents -->
       <MachineDocumentsCard
+        v-if="d.isEditMode.value || d.machineDocumentsList.value.length > 0"
         :documents="d.machineDocumentsList.value"
         :is-edit-mode="d.isEditMode.value"
         :uploading="d.machineDocumentsUploading.value"
@@ -92,6 +93,7 @@
 
       <!-- Produits associés -->
       <MachineProductsCard
+        v-if="d.isEditMode.value || d.machineDirectProducts.value.length > 0"
         :products="d.machineDirectProducts.value"
         :is-edit-mode="d.isEditMode.value"
         @add-product="openAddModal('product')"
@@ -100,6 +102,7 @@
 
       <!-- Components Section -->
       <MachineComponentsCard
+        v-if="d.isEditMode.value || d.components.value.length > 0"
         :components="d.components.value"
         :is-edit-mode="d.isEditMode.value"
         :collapsed="d.componentsCollapsed.value"
@@ -114,6 +117,7 @@
 
       <!-- Machine Pieces Section -->
       <MachinePiecesCard
+        v-if="d.isEditMode.value || d.machinePieces.value.length > 0"
         :pieces="d.machinePieces.value"
         :is-edit-mode="d.isEditMode.value"
         :collapsed="d.piecesCollapsed.value"