feat: add board goal schemas and validation

backend/app/schemas/__init__.py

@@ -1,5 +1,13 @@
 from app.schemas.activity_events import ActivityEventRead
 from app.schemas.agents import AgentCreate, AgentRead, AgentUpdate
+from app.schemas.approvals import ApprovalCreate, ApprovalRead, ApprovalUpdate
+from app.schemas.board_memory import BoardMemoryCreate, BoardMemoryRead
+from app.schemas.board_onboarding import (
+    BoardOnboardingAnswer,
+    BoardOnboardingConfirm,
+    BoardOnboardingRead,
+    BoardOnboardingStart,
+)
 from app.schemas.boards import BoardCreate, BoardRead, BoardUpdate
 from app.schemas.gateways import GatewayCreate, GatewayRead, GatewayUpdate
 from app.schemas.metrics import DashboardMetrics
@@ -11,6 +19,15 @@ __all__ = [
     "AgentCreate",
     "AgentRead",
     "AgentUpdate",
+    "ApprovalCreate",
+    "ApprovalRead",
+    "ApprovalUpdate",
+    "BoardMemoryCreate",
+    "BoardMemoryRead",
+    "BoardOnboardingAnswer",
+    "BoardOnboardingConfirm",
+    "BoardOnboardingRead",
+    "BoardOnboardingStart",
     "BoardCreate",
     "BoardRead",
     "BoardUpdate",