feat(consensus): discover ConsensusCapsules not present in persisted state

## Summary

`consensusChecker.RefreshState` (`internal/reality/consensus_checker.go`)
iterates only the **persisted** node scopes and refines each from the cluster. A
`ConsensusCapsule` that exists in the cluster but is absent from `state.yaml`
(installed by another tool, or state file lost/rebuilt) is never discovered —
reality can refine known nodes but cannot find unknown ones.

For a single block node this is acceptable; for multi-node consensus recovery it
is a real limitation.

## Trigger

Revisit when multi-node recovery or "adopt an existing cluster" becomes a
supported flow. Not needed for the current single-install path.

## Proposed solution

- List `ConsensusCapsule` CRs in the target namespace(s) and reconcile against
persisted scopes, adding discovered nodes to the reality map.
- Derive the scope key from the capsule via the shared
`models.ConsensusCapsuleName` / `ConsensusNodeScope` helpers so discovery and
creation stay in lockstep.

## Scope

- [ ] List capsules instead of iterating persisted scopes only
- [ ] Reconcile discovered vs. persisted nodes
- [ ] Unit tests: discover a capsule absent from persisted state

Context: raised during the consensus-node BLL right-sizing review (epic #713).

Start in internal/reality/consensus_checker.go at consensusChecker.RefreshState and trace the shared models.ConsensusCapsuleName and ConsensusNodeScope helpers. Add unit coverage for a ConsensusCapsule absent from persisted state, and verify that listing capsules reconciles discovered nodes into the reality map without breaking persisted scopes.

Written by the indexing model from the issue text.