feat(metrics): add instance_metric and instance_nic_metric models

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

backend/app/models/__init__.py

@@ -3,6 +3,7 @@ from .auth import Role, user_servers, User, ActiveSession, LoginAttempt, Blocked
 from .proxmox import OSTemplateGroup, OSTemplate, ProxmoxServer, VMInstance, VMSnapshotArchive
 from .ipam import IPAMNetwork, IPAMPool, IPAMAllocation, IPAMHistory
 from .tasks import TaskQueue, ProxmoxTask, DeployTask
+from .metrics import InstanceMetric, InstanceNicMetric
 from .settings import PanelSettings, SecuritySetting, Workspace, WorkspaceServer, WorkspaceUser
 from .misc import Notification, NotificationPreference, BackupJob, AuditLog
 
@@ -12,6 +13,7 @@ __all__ = [
     'OSTemplateGroup', 'OSTemplate', 'ProxmoxServer', 'VMInstance', 'VMSnapshotArchive',
     'IPAMNetwork', 'IPAMPool', 'IPAMAllocation', 'IPAMHistory',
     'TaskQueue', 'ProxmoxTask', 'DeployTask',
+    'InstanceMetric', 'InstanceNicMetric',
     'PanelSettings', 'SecuritySetting', 'Workspace', 'WorkspaceServer', 'WorkspaceUser',
     'Notification', 'NotificationPreference', 'BackupJob', 'AuditLog'
 ]