Expand description
Cocoon → unregister_scm_provider notification.
Emitted when vscode.scm.createSourceControl(...).dispose() fires.
Resolves the provider handle: uses the explicit handle field when
Cocoon sends it, otherwise recomputes the DJB-31 hash of scmId
that RegisterScmProvider used when it originally registered the provider
(necessary because Cocoon’s dispose path only carries the string id).