wisp skill: directive auth + serving-model + custom-domain flow
Rewrites the auth section from a "two ways" menu into a directive (run the
command, it opens the browser; don't pre-login or offer app-passwords unless
headless). Adds a serving-model section (SPA mode, _redirects, custom 404,
root-relative rewriter) and its hard limit — static files only, no per-request
OG/meta injection, so per-page link previews need an external renderer while
display pages don't. Documents the async custom-domain claim→DNS→verify→add-site
flow.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>