fix(client-ui-plugin-config): declare the browser half under dsh.client

Merging master's rename of the client manifest field left this package on the
old `dshClient` name. The row still composed and its empty node half still
activated, but the browser roster scan never matched it, so the whole settings
section vanished with no error anywhere.

verify-cordis-config now requires a packages/client package's "./client"
export and its dsh.client declaration to agree in both directions; the
composition file cannot tell a surface plugin from a Host plugin, so the
manifests are where this is checkable. The check is scoped to that group
because a Host package's "./client" export is the typed wire face its browser
consumers import, not a plugin the roster serves.

packages/client/ui-plugin-config/src/index.ts

@@ -2,7 +2,7 @@
  * Plugin configuration surface, node half. The empty apply exists so the
  * plugin appears in the host cordis.yml / Loader; the browser half ships the
  * settings section through exports["./client"], discovered from the
- * package.json dshClient declaration. Every section this page edits is owned
+ * package.json dsh.client declaration. Every section this page edits is owned
  * by the Host plugin that registered it, so this package registers no
  * namespace of its own.
  */