cleanup(tui): give xml-tool-output.ts a module header like its peers

Every other tui source file opens with a multi-line description ending
in @module; xml-tool-output.ts had only a one-line header. Align it.

packages/ui/tui/src/components/xml-tool-output.ts

@@ -1,4 +1,8 @@
-/** Conservative readable-tree rendering for model-facing text containing one XML document. */
+/**
+ * Conservative readable-tree rendering for model-facing text containing one XML
+ * document, used by the transcript's tool and context cards.
+ * @module @deepseek-ai/dsh-tui/components/xml-tool-output
+ */
 
 import { SaxesParser } from 'saxes'