Feature/default messenger delivery target (openclaw#16985) thanks @KirillShchetinin

Verified:
- pnpm build
- pnpm check
- pnpm test:macmini

Co-authored-by: KirillShchetinin <13061871+KirillShchetinin@users.noreply.github.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

src/config/types.googlechat.ts

@@ -54,6 +54,8 @@ export type GoogleChatAccountConfig = {
   groupPolicy?: GroupPolicy;
   /** Optional allowlist for space senders (user ids or emails). */
   groupAllowFrom?: Array<string | number>;
+  /** Default delivery target for CLI --deliver when no explicit --reply-to is provided. */
+  defaultTo?: string;
   /** Per-space configuration keyed by space id or name. */
   groups?: Record<string, GoogleChatGroupConfig>;
   /** Service account JSON (inline string or object). */