chore(secrets): release family 0.5.0 (FallbackEndpoints hub failover)

Bump ZB.MOM.WW.Secrets family 0.4.1 -> 0.5.0 and date the CHANGELOG
entry. All 6 packages (Abstractions, Secrets, Replicator.SqlServer,
Replicator.AkkaDotNet, Replicator.Grpc, Ui) packed and pushed to the
dohertj2-gitea feed; restore-verified from a scratch consumer with a
fresh package cache. Suite 470 passed / 0 failed / 15 skipped.

Claude-Session: https://claude.ai/code/session_014WNM4vjoVksyyBraTXSZE1

ZB.MOM.WW.Secrets/CHANGELOG.md

@@ -5,7 +5,7 @@ follows [Keep a Changelog](https://keepachangelog.com/); versions are shared acr
 package in the family (see `Directory.Build.props`) even when a given release only touches
 one of them.
 
-## 0.5.0 — Unreleased
+## 0.5.0 — 2026-08-07
 
 ### Added
 

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

@@ -5,7 +5,7 @@
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <LangVersion>latest</LangVersion>
-    <Version>0.4.1</Version>
+    <Version>0.5.0</Version>
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
     <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>