fix(mattermost): add actions config typing

extensions/mattermost/src/types.ts

@@ -44,6 +44,11 @@ export type MattermostAccountConfig = {
   blockStreamingCoalesce?: BlockStreamingCoalesceConfig;
   /** Outbound response prefix override for this channel/account. */
   responsePrefix?: string;
+  /** Action toggles for this account. */
+  actions?: {
+    /** Enable message reaction actions. Default: true. */
+    reactions?: boolean;
+  };
 };
 
 export type MattermostConfig = {