refactor(machines) : remove TypeMachine skeleton system, simplify machine creation

- Remove TypeEdit*, TypeInfoDisplay, MachineSkeletonSummary, MachineCreatePreview components
- Remove machine-skeleton pages and type pages
- Remove useMachineTypesApi, useMachineSkeletonEditor, useMachineCreateSelections composables
- Add AddEntityToMachineModal for direct entity linking
- Update machine detail/create pages for direct custom fields
- Fix SearchSelect, category display, and ipartial search filters

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

app/pages/pieces/create.vue

@@ -573,7 +573,6 @@ const submitCreation = async () => {
         createdPiece.id,
         [
           createdPiece?.typePiece?.pieceCustomFields,
-          createdPiece?.typeMachinePieceRequirement?.typePiece?.pieceCustomFields,
         ],
         { customFieldInputs, upsertCustomFieldValue, updateCustomFieldValue, toast },
       )