refactor: rename ScadaLink → ZB.MOM.WW.ScadaBridge (code + projects + namespaces)

Solution + 23 src projects + 26 test projects renamed; folders, csproj,
namespaces, and ScadaLinkDbContext/ScadaBridgeDbContext class updated.
ActorSystem "scadalink" → "scadabridge", Akka seed-node URLs migrated.
SQL roles/logins, LDAP domains, CLI command name, and CLI config dir
(~/.scadalink → ~/.scadabridge) also renamed.

Build green; 5 Host.Tests fail awaiting SQL login rename in next commit.
Pre-existing StaleTagMonitor timing flakes unchanged.

Rename script committed at tools/rename-to-scadabridge.sh.

src/ZB.MOM.WW.ScadaBridge.AuditLog/Central/AuditLogPurgedEvent.cs

@@ -0,0 +1,29 @@
+namespace ZB.MOM.WW.ScadaBridge.AuditLog.Central;
+
+/// <summary>
+/// Published on the actor-system EventStream by <see cref="AuditLogPurgeActor"/>
+/// after each successful partition switch-out. Downstream consumers (Bundle E
+/// central health collector, ops dashboards, audit trails) subscribe so a
+/// purge action is observable without the actor needing to know about any
+/// specific subscriber.
+/// </summary>
+/// <param name="MonthBoundary">
+/// The pf_AuditLog_Month lower-bound boundary that was switched out — i.e.
+/// the first instant of the purged month in UTC.
+/// </param>
+/// <param name="RowsDeleted">
+/// Approximate row count purged from the partition, sampled BEFORE the
+/// switch. Exact accounting would require a post-switch scan of the staging
+/// table, which the dance drops immediately, so this is the closest
+/// observable proxy. Zero is a valid value when the actor's enumerator
+/// included a partition the operator subsequently emptied by hand.
+/// </param>
+/// <param name="DurationMs">
+/// Wall-clock time spent inside <c>SwitchOutPartitionAsync</c> for this
+/// boundary, in milliseconds. Useful for spotting the rare slow purge
+/// without spinning up dedicated telemetry.
+/// </param>
+public sealed record AuditLogPurgedEvent(
+    DateTime MonthBoundary,
+    long RowsDeleted,
+    long DurationMs);