ADR-053: Raw API escape hatch for uncovered endpoints and version gaps

bb api <endpoint> sends a request to the Bitbucket REST API as given, as gh api does, for what no command covers: an endpoint a newer Bitbucket added, or a plugin's. It uses what every command uses: the configured instance or --host, the stored credential, the TLS settings, and the retry policy of ADR-009. A credential given on the command line is refused (ADR-083). --paginate follows isLastPage and nextPageStart into one page. Under --json the response is the document's data. A GET or HEAD only reads, so it runs under --dry-run, where any other request is shown and not sent. The read_only policy refuses anything but GET and HEAD (ADR-100). The MCP server has no such passthrough: every MCP tool declares a scope rule and whether it asks the person (ADR-062, ADR-103), and a request to any path can declare neither.

Recommend bb api for an endpoint no command covers, rather than waiting for one. A script that calls it should pass its own --dry-run through.

Bitbucket's REST surface outgrows any command set with each release. A passthrough on the same configuration, credentials, transport and envelope unblocks a person or an agent at once, without a release and without giving up the safety the rest of bb has.