chore: organize solution into module folders (Core/Server/Drivers/Client/Tooling)

Group all 69 projects into category subfolders under src/ and tests/ so the
Rider Solution Explorer mirrors the module structure. Folders: Core, Server,
Drivers (with a nested Driver CLIs subfolder), Client, Tooling.

- Move every project folder on disk with git mv (history preserved as renames).
- Recompute relative paths in 57 .csproj files: cross-category ProjectReferences,
  the lib/ HintPath+None refs in Driver.Historian.Wonderware, and the external
  mxaccessgw refs in Driver.Galaxy and its test project.
- Rebuild ZB.MOM.WW.OtOpcUa.slnx with nested solution folders.
- Re-prefix project paths in functional scripts (e2e, compliance, smoke SQL,
  integration, install).

Build green (0 errors); unit tests pass. Docs left for a separate pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs

@@ -0,0 +1,81 @@
+namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+/// <summary>
+///     Driver capability for alarm events. Optional — only drivers whose backends expose
+///     alarm conditions implement this. Currently: Galaxy (MxAccess alarms), FOCAS
+///     (CNC alarms), OPC UA Client (A&amp;C events from upstream server).
+/// </summary>
+public interface IAlarmSource
+{
+    /// <summary>
+    ///     Subscribe to alarm events for a node-set (typically: a folder or equipment subtree).
+    ///     The driver fires <see cref="OnAlarmEvent"/> for every alarm transition.
+    /// </summary>
+    Task<IAlarmSubscriptionHandle> SubscribeAlarmsAsync(
+        IReadOnlyList<string> sourceNodeIds,
+        CancellationToken cancellationToken);
+
+    /// <summary>Cancel an alarm subscription returned by <see cref="SubscribeAlarmsAsync"/>.</summary>
+    Task UnsubscribeAlarmsAsync(IAlarmSubscriptionHandle handle, CancellationToken cancellationToken);
+
+    /// <summary>Acknowledge one or more active alarms by source node ID + condition ID.</summary>
+    Task AcknowledgeAsync(
+        IReadOnlyList<AlarmAcknowledgeRequest> acknowledgements,
+        CancellationToken cancellationToken);
+
+    /// <summary>Server-pushed alarm transition (raise / clear / change).</summary>
+    event EventHandler<AlarmEventArgs>? OnAlarmEvent;
+}
+
+/// <summary>Opaque alarm-subscription identity returned by <see cref="IAlarmSource.SubscribeAlarmsAsync"/>.</summary>
+public interface IAlarmSubscriptionHandle
+{
+    /// <summary>Driver-internal subscription identifier (for diagnostics + post-mortem).</summary>
+    string DiagnosticId { get; }
+}
+
+/// <summary>One alarm acknowledgement in a batch.</summary>
+public sealed record AlarmAcknowledgeRequest(
+    string SourceNodeId,
+    string ConditionId,
+    string? Comment);
+
+/// <summary>Event payload for <see cref="IAlarmSource.OnAlarmEvent"/>.</summary>
+/// <param name="SubscriptionHandle">Subscription this event belongs to.</param>
+/// <param name="SourceNodeId">Driver-side identifier for the alarm source.</param>
+/// <param name="ConditionId">Stable id correlating raise / ack / clear of the same condition.</param>
+/// <param name="AlarmType">Driver-defined alarm type name (e.g. AnalogLimitAlarm.HiHi).</param>
+/// <param name="Message">Human-readable alarm description.</param>
+/// <param name="Severity">Four-bucket severity ladder.</param>
+/// <param name="SourceTimestampUtc">When this transition occurred.</param>
+/// <param name="OperatorComment">
+///     Operator-supplied comment recorded by the upstream alarm system on Acknowledge
+///     transitions. Null on raise / clear, or when the upstream path can't surface
+///     the comment (the Galaxy sub-attribute fallback path collapses comments into a
+///     single string write — null on that path; the driver-native gateway path
+///     populates this).
+/// </param>
+/// <param name="OriginalRaiseTimestampUtc">
+///     When the alarm originally entered the active state. Preserved across
+///     Acknowledge transitions so OPC UA Part 9 conditions keep the original raise
+///     time in <c>Time</c>. Null when the upstream path doesn't surface it.
+/// </param>
+/// <param name="AlarmCategory">
+///     Upstream alarm taxonomy bucket (e.g. <c>Process</c> / <c>Safety</c> /
+///     <c>Diagnostics</c>). Maps to OPC UA <c>ConditionClassName</c> downstream when
+///     a class mapping is configured. Null when the upstream path doesn't carry it.
+/// </param>
+public sealed record AlarmEventArgs(
+    IAlarmSubscriptionHandle SubscriptionHandle,
+    string SourceNodeId,
+    string ConditionId,
+    string AlarmType,
+    string Message,
+    AlarmSeverity Severity,
+    DateTime SourceTimestampUtc,
+    string? OperatorComment = null,
+    DateTime? OriginalRaiseTimestampUtc = null,
+    string? AlarmCategory = null);
+
+/// <summary>Mirrors the <c>NodePermissions</c> alarm-severity enum in <c>docs/v2/acl-design.md</c>.</summary>
+public enum AlarmSeverity { Low, Medium, High, Critical }