feat(secrets): cluster replication via SQL Server and Akka.NET (G-7, 0.2.0)

Secrets were per-node SQLite, so a secret written on one node was invisible to
the rest of a cluster. G-7's design resolved the "shared SQL store vs Akka
replicator" fork to build only the former; both are built here so the choice is
a deployment decision (availability vs partition tolerance) rather than a
library limitation.

Two new packages — ZB.MOM.WW.Secrets.Replicator.SqlServer (shared store, plus a
local-store-with-hub mode) and .Replicator.AkkaDotNet (peer-to-peer over
distributed pub/sub). Core gains ISecretsStoreMigrator, one shared
SecretLastWriterWins predicate so no two stores can disagree on a tie, the
transport-agnostic reconciler, and ReplicatingSecretStore — which closes a real
gap: nothing had ever called ISecretReplicator.PublishAsync, so the seam was
inert and local writes would not have propagated at all.

Verified 182 pass / 1 skip / 0 warnings, including 15 live tests against a real
SQL Server 2022 (the SQLite suite ported case-for-case, so any behavioural
divergence between the stores fails) and a 9-test in-process 2-node Akka
cluster over real remoting. A post-build review caught six defects, all fixed
and now covered: both replication modes could not resolve from the container
(no test had built one), an unbounded fetch that broke past SQL Server's
2100-parameter cap, a poison row that aborted the rest of its batch forever,
Enum.Parse on peer input that could restart the actor in a loop, null crypto
blobs crossing the trust boundary, and a silently dropped pull-read failure.

Packed at 0.2.0 and vulnerability-scanned clean; not yet published to the feed.

Claude-Session: https://claude.ai/code/session_01BL2Vu1ESDQ9SCN4gVKkdts

ZB.MOM.WW.Secrets/Directory.Build.props

@@ -5,7 +5,7 @@
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <LangVersion>latest</LangVersion>
-    <Version>0.1.3</Version>
+    <Version>0.2.0</Version>
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
     <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>