security: require org-admin for gateway session message endpoint

send_gateway_session_message only required basic auth (AUTH_DEP) while
all other gateway endpoints required ORG_ADMIN_DEP. Any authenticated
user could send messages to any gateway session. Now requires org-admin
and verifies the board belongs to the caller's organization.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/api/gateway.py

@@ -127,6 +127,7 @@ async def send_gateway_session_message(
     board_id: str | None = BOARD_ID_QUERY,
     session: AsyncSession = SESSION_DEP,
     auth: AuthContext = AUTH_DEP,
+    ctx: OrganizationContext = ORG_ADMIN_DEP,
 ) -> OkResponse:
     """Send a message into a specific gateway session."""
     service = GatewaySessionService(session)
@@ -134,6 +135,7 @@ async def send_gateway_session_message(
         session_id=session_id,
         payload=payload,
         board_id=board_id,
+        organization_id=ctx.organization.id,
         user=auth.user,
     )
     return OkResponse()

backend/app/services/openclaw/session_service.py

@@ -378,9 +378,12 @@ class GatewaySessionService(OpenClawDBService):
         session_id: str,
         payload: GatewaySessionMessageRequest,
         board_id: str | None,
+        organization_id: UUID | None = None,
         user: User | None,
     ) -> None:
         board, config, main_session = await self.require_gateway(board_id, user=user)
+        if organization_id is not None:
+            self._require_same_org(board, organization_id)
         if user is None:
             raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED)
         await require_board_access(self.session, user=user, board=board, write=True)