feat(acl): keys + ACLs reach driver-only nodes via the artifact (#520 stage 4)

A driver-only node has had no ConfigDb since per-cluster mesh Phase 4, so it
registered NullOpcUaUserAuthenticator and denied every UserName token. Its keys
now ride the deployment artifact instead.

- ConfigComposer snapshots ApiKeys alongside the NodeAcls it already carried.
  Only the peppered HMAC ships, never a secret, and the pepper is node config
  that is deliberately not in the artifact.
- DeploymentArtifact.ParseDataPlaneAuthority decodes both node-side. Grants are
  scoped to the node's own cluster; keys are not, because ApiKey carries no
  ClusterId — a key is a fleet-wide credential and the ACL rows are what bind it.
- OpcUaPublishActor installs them on DataPlaneAuthorityState on every apply,
  BEFORE its plan.IsEmpty early-return: an artifact that only revokes a key
  produces an empty address-space plan, so feeding after that return would leave
  the revoked key working until an unrelated structural change redeployed.
- ArtifactApiKeyStore serves them to session activation; a node with a ConfigDb
  keeps ConfigDbApiKeyStore, whose per-request read is what makes revocation
  immediate there.
- OtOpcUaNodeManager gains DataPlaneAuthority — the cluster identity blocker #4
  named. NodeScope.ClusterId is required and the evaluator fails closed on a
  mismatch, so until now no scope it built could have evaluated. Nothing reads it
  until stages 5/6.

The generation is a node-local COUNTER driven by the RevisionHash, not derived
from its bits. PermissionTrieCache treats the highest GenerationId as current, so
a generation taken from hash bytes would install a lower number about half the
time and the cache would go on serving the previous deployment's ACLs, silently.

Sessions are not stamped with it yet — that belongs with the first seam that
reads a UserAuthorizationState, in stage 5, rather than being built now and
consulted by nothing.

Live-gated on docker-dev against site-a-1 (driver-only, no ConfigDb): key
authenticates, wrong secret denied, both halves of the revocation asymmetry
observed, and a SITE-A grant confirmed not to reach site-b-1. Key minted with an
independent Python HMAC so the verifier was checked against something other than
itself. Rig left clean.

Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo

src/Server/ZB.MOM.WW.OtOpcUa.Host/OpcUa/ConfigDbApiKeyStore.cs

@@ -10,12 +10,12 @@ namespace ZB.MOM.WW.OtOpcUa.Host.OpcUa;
 ///     that has a ConfigDb — i.e. one carrying the <c>admin</c> role, including a fused admin+driver node.
 /// </summary>
 /// <remarks>
-///     ⚠️ <b>A driver-only node has no ConfigDb since per-cluster mesh Phase 4</b>, so this store cannot
-///     be registered there and such a node has no key source until the artifact-backed store lands in
-///     stage 4. Until then a driver-only node authenticates no UserName tokens at all — it falls to
-///     <see cref="OpcUaServer.Security.NullOpcUaUserAuthenticator"/>, which denies every attempt. That is
-///     the safe direction, and anonymous sessions (still permitted, and still unrestricted until
-///     enforcement lands in stages 5–6) are unaffected.
+///     <b>A driver-only node has no ConfigDb since per-cluster mesh Phase 4</b>, so this store cannot be
+///     registered there; that node uses <see cref="ArtifactApiKeyStore"/> instead (#520 stage 4).
+///     <para>
+///         Reading per request is what makes revocation immediate here, which is why this store is
+///         preferred wherever a ConfigDb exists — including on a fused admin+driver node.
+///     </para>
 /// </remarks>
 public sealed class ConfigDbApiKeyStore : IApiKeyStore
 {