Story 5.6 — Implement idempotent ConsensusConfig CR creation with operation-id label check

**Epic:** #502 — Network Upgrade Workflow (Execute Phase)

Make ConsensusConfig CR creation idempotent so re-runs of the execute phase do not create duplicate CRs.

**Acceptance criteria:**
- Before creating a CR, check if a CR of the same kind with a matching `hedera.com/operation-id` label already exists.
- If it exists, skip creation and watch that CR's status instead of creating a new one.
- Log a clear message when skipping due to idempotency.

**Blocked on:** solo-operator CRD contract.
**Depends on:** #541.