* docs: boost search ranking for single-word title pages
Apply `boost: 3` to English pages whose H1 / frontmatter title is a single word (e.g. "Assistant", "Quickstart", "Cards"). Short titles tend to be canonical landing pages for a topic, so users searching the exact term should land on them first.
* docs: drop boost on websocket-playground stub to keep canonical Playground ranking
`api-playground/websocket-playground.mdx` is an auto-generated AsyncAPI stub with no body content but shares the title "Playground" with `api-playground/overview.mdx`. Boosting both equally diluted the canonical overview page in search for the query "playground". Drop the boost on the stub.
skeptrune