Wiki setup

Connect the internal Notion workspace

The wiki route now reads from environment variables instead of a hardcoded token. Add these variables to `apps/rare-auth/.env.local` or your shared env source, then reload `/wiki`.

`NOTION_TOKEN_V2` should be the `token_v2` cookie value from a Notion session, and `NOTION_WIKI_ROOT_PAGE_ID` should point at the root wiki page you want to mirror.