add total stream/consumer counts to meta snapshot stats

[alexbozhenko]

Signed-off-by: Your Name your.email@example.com

[synadia-claude-reviewer]

Claude finished @alexbozhenko's task in 1m 42s —— View job

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Two issues found:

1. Data race (critical) — server/monitor.go:3040-3041

totalStreamCount and totalConsumerCount are written with atomic.StoreInt64 in encodeMetaSnapshot, but read without atomic loads in metaClusterSnapshotStats. The race detector will flag this. The fix is to use atomic.LoadInt64(...) matching the existing pattern for lastMetaSnapTime/lastMetaSnapDuration just above.

2. Stale counts when all streams are deleted — server/jetstream_cluster.go:2147-2151

The if len(out) == 0 early return (before the atomic-store block) is taken when there are no streams, so totalStreamCount and totalConsumerCount are never updated to 0. A cluster that had N streams and then had all of them deleted would continue to show the old counts until the next non-empty snapshot. The fix is to move the count stores before (or duplicate them in) the early-return branch.

[synadia-claude-reviewer]

Data race: totalStreamCount and totalConsumerCount are written with atomic.StoreInt64 in encodeMetaSnapshot, but read here without atomic loads. The race detector will flag this.

Suggested change

	snap.TotalStreamCount = uint64(cluster.totalStreamCount)
	snap.TotalStreamCount = uint64(atomic.LoadInt64(&cluster.totalStreamCount))
	snap.TotalConsumerCount = uint64(atomic.LoadInt64(&cluster.totalConsumerCount))

This matches the existing pattern used for lastMetaSnapTime and lastMetaSnapDuration just above.

[synadia-claude-reviewer]

The if len(out) == 0 early return on the non-diff path (before this block) skips these stores. So if all streams are deleted, totalStreamCount and totalConsumerCount remain at their previous non-zero values rather than being updated to 0.

Consider moving the entire atomic-store block (or at least the count stores) to before the len(out) == 0 check, since nsa and nca are fully computed by that point.