Migrate from Verdaccio to AngusRepo: uplinks, scopes, tokens, and catch-up, dual run, and rollback

Move the npm packages you published on Verdaccio into AngusRepo: how storage, uplinks, and htpasswd map over, an idempotent catch-up script, .npmrc and lockfile edits, a dual-run, cutover, and rollback checklist, and the hidden trap of reset publish times.