* test(io-metrics): assert lib.rs record helper emissions
The 29 assertion-less record_* smoke tests in io-metrics/src/lib.rs called
their helpers and checked nothing; because METRICS_ENABLED defaults to
false they did not even reach the emission bodies. Replace them with six
DebuggingRecorder tests that enable the gate, pin every metric name the
helpers own, and pin the derived values, branch selection and label
mapping (rustfs/backlog#1836).
* test(tooling): anchor assertless-census delegation tokens to name segments
Zhengchao An