Fix CodeQL error-level findings: dead branches, log arguments, locking, clone

[vharseko]

Summary

Closes all 25 open error-level (code quality) CodeQL alerts: #470–#486, #490–#494, #497–#499. Most are mechanical, but three turned out to be real bugs (marked bug below).

Alerts	File	Change
#477–#486 contradictory-type-checks	ReconciliationService	Removed the five unreachable else if (… instanceof ScheduledThreadPoolExecutor) branches — it is a ThreadPoolExecutor, so the first branch always wins.
#470–#476 missing-format-argument	ClusterManager, ConnectorInfoProviderService, Id, GenericTableHandler, MappedTableHandler ×2, PostgreSQLMappedTableHandler	Placeholders and arguments reconciled: missing instanceId; new Object[]{…}, e → plain varargs with the throwable last; stray {} dropped; the "Unprepared query strings" debug line was missing readForUpdateQueryStr.
#497 type-mismatch-access — bug	ExplicitResultSetMapper	columnMappings.contains("total") compared a String against a List<ColumnMapping> and was always false, so an explicitly mapped total column was silently overwritten with rs.getInt("total"). Now checks the mapped DB column names.
#493/#494 unsafe-sync-on-field / unsafe-double-checked-locking — bug	AbstractScriptedService	synchronized (selfRegistration) while selfRegistration == null → NullPointerException on every REGISTERED script event (the new test reproduced it). Now a dedicated registrationLock, a volatile field, and the field is cleared after unregister() so a script reload re-registers instead of leaving a stale registration.
#491 missing-clone-method — bug	JsonUser	JsonValue.clone() returns a plain JsonValue, so cloning a JsonUser lost the User type and its CryptoService. Overridden.
#490 missing-clone-method	ChecksumFile	clone() override (shallow, like HashMap; documented).
#492 sleep-with-lock-held	OrientDBRepoService	The 100 ms back-off between pool-acquire retries now happens outside dbLock; only the pool.acquire call is serialised. InterruptedException restores the interrupt flag and stops retrying instead of being swallowed.
#498/#499 unused-container	OperationHelperImpl, RepoJobStore	Removed resultList (only referenced from commented-out code) and blockedJobs (added/removed, never read) plus the else {} that became empty.

Test plan

• New ExplicitResultSetMapperTest (2), AbstractScriptedServiceTest (3), JsonUserTest (2), ChecksumFileTest.testCloneKeepsEntriesAndType — all failed before the change (2× compile error, 1× NPE, 1× overwritten value), pass now
• Full test suites of the 10 touched modules: core 23, cluster 3, provisioner-openicf 142, provisioner 5, repo-jdbc 3, maintenance 116, workflow-activiti 3, repo-orientdb 31, script 11, quartz-fragment 16 — 0 failures
• CodeQL on this PR closes #470–#486, #490–#494, #497–#499