feat(machine) : allow site editing on machine detail page and align card buttons

- Add site select field in MachineInfoCard (edit mode)
- Include siteId in machine PATCH payload
- Align action buttons (Modifier/Supprimer/Détails) consistently at card bottom
- Use mt-auto + flex-col to push buttons to bottom across all machine cards

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/pages/machine/[id].vue

@@ -53,6 +53,9 @@
         :is-edit-mode="d.isEditMode.value"
         :machine-name="d.machineName.value"
         :machine-reference="d.machineReference.value"
+        :machine-site-id="d.machineSiteId.value"
+        :machine-site-name="d.machine.value?.site?.name ?? ''"
+        :sites="d.sites.value"
         :machine-constructeur-ids="d.machineConstructeurIds.value"
         :machine-constructeurs-display="d.machineConstructeursDisplay.value"
         :has-machine-constructeur="d.hasMachineConstructeur.value"
@@ -62,6 +65,7 @@
         :machine-custom-field-defs="d.machine.value?.customFields ?? []"
         @update:machine-name="d.machineName.value = $event"
         @update:machine-reference="d.machineReference.value = $event"
+        @update:machine-site-id="d.machineSiteId.value = $event"
         @update:constructeur-ids="d.handleMachineConstructeurChange"
         @blur-field="d.updateMachineInfo"
         @set-custom-field-value="d.setMachineCustomFieldValue"