feat: add board webhook configuration and payload models

backend/app/api/organizations.py

@@ -24,6 +24,8 @@ from app.models.board_group_memory import BoardGroupMemory
 from app.models.board_groups import BoardGroup
 from app.models.board_memory import BoardMemory
 from app.models.board_onboarding import BoardOnboardingSession
+from app.models.board_webhook_payloads import BoardWebhookPayload
+from app.models.board_webhooks import BoardWebhook
 from app.models.boards import Board
 from app.models.gateways import Gateway
 from app.models.organization_board_access import OrganizationBoardAccess
@@ -290,6 +292,18 @@ async def delete_my_org(
         col(BoardMemory.board_id).in_(board_ids),
         commit=False,
     )
+    await crud.delete_where(
+        session,
+        BoardWebhookPayload,
+        col(BoardWebhookPayload.board_id).in_(board_ids),
+        commit=False,
+    )
+    await crud.delete_where(
+        session,
+        BoardWebhook,
+        col(BoardWebhook.board_id).in_(board_ids),
+        commit=False,
+    )
     await crud.delete_where(
         session,
         BoardOnboardingSession,