feat(ui): add source indicators to slash commands (#18839)

packages/cli/src/ui/commands/types.ts

@@ -191,6 +191,12 @@ export interface SlashCommand {
 
   kind: CommandKind;
 
+  /**
+   * Optional namespace for the command (e.g., 'user', 'workspace', 'extensionName').
+   * If provided, the command will be registered as 'namespace:name'.
+   */
+  namespace?: string;
+
   /**
    * Controls whether the command auto-executes when selected with Enter.
    *