feat: add board group models and update related interfaces

backend/app/schemas/board_group_heartbeat.py

@@ -0,0 +1,21 @@
+from __future__ import annotations
+
+from typing import Any
+from uuid import UUID
+
+from sqlmodel import SQLModel
+
+
+class BoardGroupHeartbeatApply(SQLModel):
+    # Heartbeat cadence string understood by the OpenClaw gateway (e.g. "2m", "10m", "30m").
+    every: str
+    # Optional heartbeat target (most deployments use "none").
+    target: str | None = None
+    include_board_leads: bool = False
+
+
+class BoardGroupHeartbeatApplyResult(SQLModel):
+    board_group_id: UUID
+    requested: dict[str, Any]
+    updated_agent_ids: list[UUID]
+    failed_agent_ids: list[UUID]