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/Client/ZB.MOM.WW.OtOpcUa.Client.CLI.Tests/SubscribeCommandTests.cs

@@ -0,0 +1,108 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Client.CLI.Commands;
+using ZB.MOM.WW.OtOpcUa.Client.CLI.Tests.Fakes;
+
+namespace ZB.MOM.WW.OtOpcUa.Client.CLI.Tests;
+
+public class SubscribeCommandTests
+{
+    [Fact]
+    public async Task Execute_SubscribesWithCorrectParameters()
+    {
+        var fakeService = new FakeOpcUaClientService();
+        var factory = new FakeOpcUaClientServiceFactory(fakeService);
+        var command = new SubscribeCommand(factory)
+        {
+            Url = "opc.tcp://localhost:4840",
+            NodeId = "ns=2;s=TestVar",
+            Interval = 500
+        };
+
+        using var console = TestConsoleHelper.CreateConsole();
+
+        // The subscribe command waits for cancellation. We need to cancel it.
+        // Use the console's cancellation to trigger stop.
+        var task = Task.Run(async () => { await command.ExecuteAsync(console); });
+
+        // Give it a moment to subscribe, then cancel
+        await Task.Delay(100);
+        console.RequestCancellation();
+        await task;
+
+        fakeService.SubscribeCalls.Count.ShouldBe(1);
+        fakeService.SubscribeCalls[0].IntervalMs.ShouldBe(500);
+        fakeService.SubscribeCalls[0].NodeId.Identifier.ShouldBe("TestVar");
+    }
+
+    [Fact]
+    public async Task Execute_UnsubscribesOnCancellation()
+    {
+        var fakeService = new FakeOpcUaClientService();
+        var factory = new FakeOpcUaClientServiceFactory(fakeService);
+        var command = new SubscribeCommand(factory)
+        {
+            Url = "opc.tcp://localhost:4840",
+            NodeId = "ns=2;s=TestVar"
+        };
+
+        using var console = TestConsoleHelper.CreateConsole();
+
+        var task = Task.Run(async () => { await command.ExecuteAsync(console); });
+
+        await Task.Delay(100);
+        console.RequestCancellation();
+        await task;
+
+        fakeService.UnsubscribeCalls.Count.ShouldBe(1);
+    }
+
+    [Fact]
+    public async Task Execute_DisconnectsInFinally()
+    {
+        var fakeService = new FakeOpcUaClientService();
+        var factory = new FakeOpcUaClientServiceFactory(fakeService);
+        var command = new SubscribeCommand(factory)
+        {
+            Url = "opc.tcp://localhost:4840",
+            NodeId = "ns=2;s=TestVar"
+        };
+
+        using var console = TestConsoleHelper.CreateConsole();
+
+        var task = Task.Run(async () => { await command.ExecuteAsync(console); });
+
+        await Task.Delay(100);
+        console.RequestCancellation();
+        await task;
+
+        fakeService.DisconnectCalled.ShouldBeTrue();
+        fakeService.DisposeCalled.ShouldBeTrue();
+    }
+
+    [Fact]
+    public async Task Execute_PrintsSubscriptionMessage()
+    {
+        var fakeService = new FakeOpcUaClientService();
+        var factory = new FakeOpcUaClientServiceFactory(fakeService);
+        var command = new SubscribeCommand(factory)
+        {
+            Url = "opc.tcp://localhost:4840",
+            NodeId = "ns=2;s=TestVar",
+            Interval = 2000
+        };
+
+        using var console = TestConsoleHelper.CreateConsole();
+
+        var task = Task.Run(async () => { await command.ExecuteAsync(console); });
+
+        await Task.Delay(100);
+        console.RequestCancellation();
+        await task;
+
+        var output = TestConsoleHelper.GetOutput(console);
+        // CLI now prints aggregate form "Subscribed to {count}/{total} nodes (interval: ...)" rather than
+        // the single-node form the original test asserted — the command supports multi-node now.
+        output.ShouldContain("Subscribed to 1/1 nodes (interval: 2000ms)");
+    }
+}