fix: add root to workspaces so changesets can version the codeman package

@manypkg/get-packages only includes workspace members in its packages list,
not the workspace root. Adding "." to workspaces makes the root package
discoverable, fixing "not in the workspace" errors from changeset version.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -29,6 +29,7 @@
     "release": "changeset publish"
   },
   "workspaces": [
+    ".",
     "packages/*"
   ],
   "keywords": [