fix: propagate TenantID in team task dispatch InboundMessage

dispatchTaskToAgent() constructed InboundMessage without TenantID,
causing DB-level MCP servers to be invisible when dispatching team
tasks from the dashboard. Same root cause as #560.

internal/gateway/methods/teams_tasks_mutations.go

@@ -405,6 +405,7 @@ func (m *TeamsMethods) dispatchTaskToAgent(ctx context.Context, task *store.Team
 		Content:  content,
 		UserID:   userID,
 		AgentID:  ag.AgentKey,
+		TenantID: store.TenantIDFromContext(ctx),
 		Metadata: meta,
 	})
 	slog.Info("teams.tasks.dispatch: sent task to agent",