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>

tests/Server/ZB.MOM.WW.OtOpcUa.Server.Tests/Alarms/DriverAlarmSourceAcknowledgerRoutingTests.cs

@@ -0,0 +1,72 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Tests.Alarms;
+
+/// <summary>
+///     PR B.3 — pins the routing decision DriverNodeManager makes when registering
+///     an AlarmConditionState: drivers that implement <see cref="IAlarmSource"/>
+///     get an acknowledger that calls AcknowledgeAsync (driver-native path); drivers
+///     that don't fall back to the IWritable sub-attribute write.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class DriverAlarmSourceAcknowledgerRoutingTests
+{
+    [Fact]
+    public void Driver_with_IAlarmSource_is_recognized()
+    {
+        IDriver driver = new FakeDriverWithAlarmSource("drv-1");
+        (driver is IAlarmSource).ShouldBeTrue(
+            "fakes that participate in the routing-test fixture must report IAlarmSource");
+    }
+
+    [Fact]
+    public void Driver_without_IAlarmSource_falls_to_writable_path()
+    {
+        IDriver driver = new FakeDriverNoAlarmSource("drv-2");
+        (driver is IAlarmSource).ShouldBeFalse(
+            "drivers without IAlarmSource take the legacy DriverWritableAcknowledger path");
+    }
+
+    private sealed class FakeDriverWithAlarmSource(string id) : IDriver, IAlarmSource
+    {
+        public string DriverInstanceId { get; } = id;
+        public string DriverType => "FakeAlarmSource";
+        public Task InitializeAsync(string c, CancellationToken ct) => Task.CompletedTask;
+        public Task ReinitializeAsync(string c, CancellationToken ct) => Task.CompletedTask;
+        public Task ShutdownAsync(CancellationToken ct) => Task.CompletedTask;
+        public DriverHealth GetHealth() => new(DriverState.Healthy, DateTime.UtcNow, null);
+        public long GetMemoryFootprint() => 0;
+        public Task FlushOptionalCachesAsync(CancellationToken ct) => Task.CompletedTask;
+
+        public Task<IAlarmSubscriptionHandle> SubscribeAlarmsAsync(
+            IReadOnlyList<string> sourceNodeIds, CancellationToken cancellationToken)
+            => Task.FromResult<IAlarmSubscriptionHandle>(new FakeHandle("h"));
+        public Task UnsubscribeAlarmsAsync(IAlarmSubscriptionHandle handle, CancellationToken cancellationToken)
+            => Task.CompletedTask;
+        public Task AcknowledgeAsync(
+            IReadOnlyList<AlarmAcknowledgeRequest> acknowledgements, CancellationToken cancellationToken)
+            => Task.CompletedTask;
+
+        public event EventHandler<AlarmEventArgs>? OnAlarmEvent;
+        private void NoUnusedWarning() => OnAlarmEvent?.Invoke(this, null!);
+    }
+
+    private sealed class FakeDriverNoAlarmSource(string id) : IDriver
+    {
+        public string DriverInstanceId { get; } = id;
+        public string DriverType => "FakeNoAlarmSource";
+        public Task InitializeAsync(string c, CancellationToken ct) => Task.CompletedTask;
+        public Task ReinitializeAsync(string c, CancellationToken ct) => Task.CompletedTask;
+        public Task ShutdownAsync(CancellationToken ct) => Task.CompletedTask;
+        public DriverHealth GetHealth() => new(DriverState.Healthy, DateTime.UtcNow, null);
+        public long GetMemoryFootprint() => 0;
+        public Task FlushOptionalCachesAsync(CancellationToken ct) => Task.CompletedTask;
+    }
+
+    private sealed class FakeHandle(string id) : IAlarmSubscriptionHandle
+    {
+        public string DiagnosticId { get; } = id;
+    }
+}