fix: normalize delivery routing context

Co-authored-by: adam91holt <adam91holt@users.noreply.github.com>

src/gateway/session-utils.types.ts

@@ -1,4 +1,5 @@
 import type { SessionEntry } from "../config/sessions.js";
+import type { DeliveryContext } from "../utils/delivery-context.js";
 
 export type GatewaySessionsDefaults = {
   modelProvider: string | null;
@@ -32,6 +33,7 @@ export type GatewaySessionRow = {
   modelProvider?: string;
   model?: string;
   contextTokens?: number;
+  deliveryContext?: DeliveryContext;
   lastChannel?: SessionEntry["lastChannel"];
   lastTo?: string;
   lastAccountId?: string;