* fix(readiness): gate on lock quorum health
Include distributed lock quorum in runtime readiness decisions and expose the signal in health responses.
Map namespace lock quorum failures to ServiceUnavailable instead of InternalError so clients can safely retry while keeping quorum enforcement unchanged.
* fix(ecstore): restore namespace lock error decoding
Add the missing from_u32 arm for NamespaceLockQuorumUnavailable and cover the numeric roundtrip in error tests.