fix(gateway): avoid whatsapp fallback for internal runs

src/utils/message-provider.ts

@@ -8,6 +8,41 @@ export function normalizeMessageProvider(
   return normalized;
 }
 
+export type GatewayMessageProvider =
+  | "whatsapp"
+  | "telegram"
+  | "discord"
+  | "slack"
+  | "signal"
+  | "imessage"
+  | "msteams"
+  | "webchat";
+
+const GATEWAY_MESSAGE_PROVIDERS: GatewayMessageProvider[] = [
+  "whatsapp",
+  "telegram",
+  "discord",
+  "slack",
+  "signal",
+  "imessage",
+  "msteams",
+  "webchat",
+];
+
+export function isGatewayMessageProvider(
+  value: string,
+): value is GatewayMessageProvider {
+  return (GATEWAY_MESSAGE_PROVIDERS as string[]).includes(value);
+}
+
+export function resolveGatewayMessageProvider(
+  raw?: string | null,
+): GatewayMessageProvider | undefined {
+  const normalized = normalizeMessageProvider(raw);
+  if (!normalized) return undefined;
+  return isGatewayMessageProvider(normalized) ? normalized : undefined;
+}
+
 export function resolveMessageProvider(
   primary?: string | null,
   fallback?: string | null,