[Pipe] Fix procedure diagnostic Sonar issues

[Caideyipi]

Description

Follow-up to #18297.

• Replace volatile mutable diagnostic references with AtomicReference.
• Preserve the live pending-DataNode view backed by ConcurrentHashMap.keySet().
• Make the non-null state contract explicit before state switches.
• Parameterize LockQueue so its owner getter no longer exposes a wildcard type.
• Use pattern matching and a Checkstyle-compatible switch layout.
• Document the no-op tracker and suppress unavoidable line-length warnings caused by generated i18n identifiers.

Tests

• mvn -pl iotdb-core/confignode -Dtest=AbstractOperatePipeProcedureV2Test,TestLockRegime -Ddevelocity.off=true test (7 tests)
• mvn -pl iotdb-core/confignode checkstyle:check
• mvn -pl iotdb-core/confignode spotless:apply
• git diff --check