Search across your own connected-account content and return the best matches.
Each result has an `id` (pass it to `fetch` for the full item), a `title`, a `url`, and
a `text` snippet. This is the deep-research "search" entrypoint the ChatGPT/Claude
connectors call by convention; for semantic search over analyzed videos specifically use
`search_videos`. Returns {"results": [...]}; when you have no connected accounts it
returns reason="no_connected_accounts" plus a connect_url instead of results.
ConnectorOAuth