add storage foundation contracts

domain/workspace.py

@@ -0,0 +1,17 @@
+from dataclasses import dataclass
+from datetime import datetime
+from uuid import UUID
+
+
+@dataclass(frozen=True, slots=True)
+class Workspace:
+    workspace_id: UUID
+    user_id: UUID
+    created_at: datetime
+
+
+@dataclass(frozen=True, slots=True)
+class WorkspaceUsage:
+    workspace_id: UUID
+    used_bytes: int
+    quota_bytes: int