feat(versioning) : add entity versioning with numbered versions and restore

Backend:
- Migration: version column on audit_logs and machines
- AuditLog, Machine, Composant, Piece, Product: version + skipAudit properties
- AbstractAuditSubscriber: auto-increment version, skip on restore, fix decimal diff
- Enriched snapshots with slots, custom fields and version number
- AuditLogRepository: findVersionHistory, findByVersion
- EntityVersionService: list, preview, restore with skeleton/integrity checks
- EntityVersionController: REST endpoints for all 4 entity types
- 11 tests covering list, preview, restore, auth

Frontend: update submodule pointer

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

src/Entity/Piece.php

@@ -133,6 +133,8 @@ class Piece
     #[Groups(['piece:read'])]
     private int $version = 1;
 
+    private bool $skipAudit = false;
+
     #[ORM\Column(type: Types::DATETIME_IMMUTABLE, name: 'createdAt')]
     #[Groups(['piece:read'])]
     private DateTimeImmutable $createdAt;
@@ -354,4 +356,16 @@ class Piece
 
         return $this;
     }
+
+    public function getSkipAudit(): bool
+    {
+        return $this->skipAudit;
+    }
+
+    public function setSkipAudit(bool $skipAudit): static
+    {
+        $this->skipAudit = $skipAudit;
+
+        return $this;
+    }
 }