feat(gateways): Introduce gateway model and update agent provisioning templates

backend/app/schemas/gateways.py

@@ -0,0 +1,34 @@
+from __future__ import annotations
+
+from datetime import datetime
+from uuid import UUID
+
+from sqlmodel import SQLModel
+
+
+class GatewayBase(SQLModel):
+    name: str
+    url: str
+    main_session_key: str
+    workspace_root: str
+    skyll_enabled: bool = False
+
+
+class GatewayCreate(GatewayBase):
+    token: str | None = None
+
+
+class GatewayUpdate(SQLModel):
+    name: str | None = None
+    url: str | None = None
+    token: str | None = None
+    main_session_key: str | None = None
+    workspace_root: str | None = None
+    skyll_enabled: bool | None = None
+
+
+class GatewayRead(GatewayBase):
+    id: UUID
+    token: str | None = None
+    created_at: datetime
+    updated_at: datetime