Add ActiveCheck initialization ownership switch

[fabrizio2210]

Context

SCHED-1967 moves mandatory cluster initialization into the Slurm-cluster HelmRelease before ActiveChecks diagnostics are decoupled from Terraform apply. This compatibility-first PR prepares the ActiveChecks chart while preserving existing behavior by default.

Changes

• add clusterInitialization.managedBySlurmCluster, disabled by default
• suppress legacy initialization ActiveChecks and their dependencies when enabled
• retain the force and dry-run jail maintenance checks
• add Helm rendering coverage for both ownership modes

Validation

• helm unittest helm/*/ (356 tests passed)
• default rendered manifests are unchanged from HEAD
• git diff --check