Phase A dynlink-mode sqlite bridge for timescale_toolkit_timevector (target timescale_toolkit_timevector).
Exports the declarative sqlite:extension@1.0.0 metadata + scalar-
function contract. metadata.describe() advertises every scalar the
catalog names; scalar-function.call(func-id, args) routes per-row
invocations through compose:dynlink/linker against the resident
provider timescale_toolkit_timevector-composed. Aggregate / vtab / hook exports are
deferred to a follow-up.