feat(machine) : add custom field definition editor on machine detail page

Adds UI to create, edit, reorder and delete custom field definitions
directly from the machine detail page in edit mode.

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

app/pages/machine/[id].vue

@@ -57,12 +57,15 @@
         :has-machine-constructeur="d.hasMachineConstructeur.value"
         :visible-custom-fields="d.visibleMachineCustomFields.value"
         :get-machine-field-id="d.getMachineFieldId"
+        :machine-id="machineId"
+        :machine-custom-field-defs="d.machine.value?.customFields ?? []"
         @update:machine-name="d.machineName.value = $event"
         @update:machine-reference="d.machineReference.value = $event"
         @update:constructeur-ids="d.handleMachineConstructeurChange"
         @blur-field="d.updateMachineInfo"
         @set-custom-field-value="d.setMachineCustomFieldValue"
         @update-custom-field="d.updateMachineCustomField"
+        @custom-fields-saved="d.loadMachineData()"
       />
 
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