Fix duplicate key error when creating VM with previously deleted VMID

- Modified save_vm_instance to check for soft-deleted records before insert
- If a soft-deleted record exists with same server_id+vmid, restore and update it
- Prevents 'duplicate key value violates unique constraint' errors

backend/app/api/proxmox.py

@@ -4090,7 +4090,7 @@ def save_vm_instance(
 ) -> VMInstance:
     """Save or update VM instance configuration"""
     
-    # Проверяем, существует ли уже запись
+    # Проверяем, существует ли уже активная запись
     existing = db.query(VMInstance).filter(
         VMInstance.server_id == server_id,
         VMInstance.vmid == vmid,
@@ -4120,7 +4120,41 @@ def save_vm_instance(
         db.commit()
         db.refresh(existing)
         return existing
-    else:
+    
+    # Проверяем, есть ли удалённая запись с тем же vmid (soft-deleted)
+    deleted_existing = db.query(VMInstance).filter(
+        VMInstance.server_id == server_id,
+        VMInstance.vmid == vmid,
+        VMInstance.deleted_at != None
+    ).first()
+    
+    if deleted_existing:
+        # Восстанавливаем и обновляем удалённую запись
+        deleted_existing.node = node
+        deleted_existing.vm_type = vm_type
+        deleted_existing.name = name
+        deleted_existing.cores = cores
+        deleted_existing.memory = memory
+        deleted_existing.disk_size = disk_size
+        deleted_existing.ip_address = ip_address
+        deleted_existing.ip_prefix = ip_prefix
+        deleted_existing.gateway = gateway
+        deleted_existing.nameserver = nameserver
+        deleted_existing.cloud_init_user = cloud_init_user
+        deleted_existing.cloud_init_password = cloud_init_password
+        deleted_existing.ssh_keys = ssh_keys
+        deleted_existing.template_id = template_id
+        deleted_existing.template_name = template_name
+        deleted_existing.description = description
+        deleted_existing.extra_config = extra_config
+        deleted_existing.owner_id = owner_id
+        deleted_existing.status = 'unknown'
+        deleted_existing.deleted_at = None  # Восстанавливаем запись
+        deleted_existing.updated_at = func.now()
+        db.commit()
+        db.refresh(deleted_existing)
+        return deleted_existing
+    
     # Создаем новую запись
     instance = VMInstance(
         server_id=server_id,