docs(components): add v5.1.3 changed badge to scope.close()

Review feedback on #647: scope.close() awaits promises returned by
'close' listeners as of v5.1.3 (v5.1.2 emitted 'close' without
awaiting). Per CONTRIBUTING.md, behavior changes to existing surface
get a standalone <VersionBadge type="changed" /> below the heading.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: Ethan-Arrowood

reference/components/plugin-api.md

@@ -189,6 +189,8 @@ Returns: `string` — Root directory of the application component (where `config
 
 #### `scope.close()`
 
+<VersionBadge type="changed" version="v5.1.3" />
+
 Closes all associated entry handlers and the `scope.options` instance, emits `'close'`, and removes all listeners. Promises returned by `'close'` listeners are awaited before it resolves.
 
 Plugins rarely call this directly. Harper calls it on each worker thread during shutdown and graceful restart — see [Cleanup on Shutdown](#cleanup-on-shutdown).