refactor(api) : remove TypeMachine skeleton system, fix ModelType serialization

- Remove TypeMachine, TypeMachineComponentRequirement, TypeMachinePieceRequirement,
  TypeMachineProductRequirement entities and related repositories/state processor
- Replace MachineSkeletonController with MachineStructureController
- Link CustomField directly to Machine instead of TypeMachine
- Add migration to drop TypeMachine tables and migrate custom fields to machines
- Fix ModelType serialization: Annotation\Groups → Attribute\Groups (Symfony 8 compat)
  and add product:read, composant:read, piece:read groups for embedded category display
- Fix Profile: same Annotation → Attribute import
- Fix SearchFilter: partial → ipartial on Comment and Document
- Update frontend submodule (remove skeleton pages/components, simplify machine creation)

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

src/Service/ModelTypeCategoryConversionService.php

@@ -137,16 +137,6 @@ final class ModelTypeCategoryConversionService
             $blockers[] = sprintf('%d pièce(s) liée(s) à des machines.', $machineLinked);
         }
 
-        // Check type machine requirements
-        $requirementCount = (int) $this->connection->fetchOne(
-            'SELECT COUNT(*) FROM type_machine_piece_requirements WHERE typepieceid = :id',
-            ['id' => $modelTypeId],
-        );
-
-        if ($requirementCount > 0) {
-            $blockers[] = sprintf('Utilisé dans %d modèle(s) de type de machine.', $requirementCount);
-        }
-
         // Check name collision with existing composants
         $collisions = $this->connection->fetchFirstColumn(
             'SELECT p.name FROM pieces p
@@ -210,16 +200,6 @@ final class ModelTypeCategoryConversionService
             $blockers[] = sprintf('%d composant(s) lié(s) à des machines.', $machineLinked);
         }
 
-        // Check type machine requirements
-        $requirementCount = (int) $this->connection->fetchOne(
-            'SELECT COUNT(*) FROM type_machine_component_requirements WHERE typecomposantid = :id',
-            ['id' => $modelTypeId],
-        );
-
-        if ($requirementCount > 0) {
-            $blockers[] = sprintf('Utilisé dans %d modèle(s) de type de machine.', $requirementCount);
-        }
-
         // Check if any composant has pieces or sub-components in structure
         $withStructure = $this->connection->fetchAllAssociative(
             'SELECT name, structure FROM composants WHERE typecomposantid = :id AND structure IS NOT NULL',