Function execute_expand_property 

pub async fn execute_expand_property<P: DavExpandPropertyProvider, C: DavCancellation>(
    provider: &P,
    root_href: &str,
    request: &DavExpandPropertyRequest,
    limits: DavReportLimits,
    cancellation: &C,
) -> Result<DavResponse, DavExpandPropertyError>

Executes one bounded DAV:expand-property request and composes canonical nested responses.

Deadline handling is supplied by the same cancellation checkpoint: a transport or product deadline flips its cancellation source, and Forge checks it before every property lookup and nested href traversal.

Errors

Returns a typed limit, cancellation, cycle, backend, or response-composition failure.