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/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/Health/HostConnectivityForwarderTests.cs

@@ -0,0 +1,83 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Health;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests.Health;
+
+/// <summary>
+///     Tests for <see cref="HostConnectivityForwarder"/>'s push path. The forwarder is a
+///     thin shim over <see cref="HostStatusAggregator"/>; the only invariants worth pinning
+///     are that SetTransport routes correctly under the configured client name and that
+///     repeated identical pushes don't produce duplicate change events (the aggregator's
+///     dedup carries that — this test asserts the forwarder doesn't re-introduce them).
+/// </summary>
+public sealed class HostConnectivityForwarderTests
+{
+    [Fact]
+    public void SetTransport_Running_PushesUnderClientName()
+    {
+        var agg = new HostStatusAggregator();
+        var captured = new List<HostStatusChangedEventArgs>();
+        agg.OnHostStatusChanged += (_, e) => captured.Add(e);
+
+        var fwd = new HostConnectivityForwarder("OtOpcUa-A", agg);
+        fwd.SetTransport(HostState.Running);
+
+        captured.Count.ShouldBe(1);
+        captured[0].HostName.ShouldBe("OtOpcUa-A");
+        captured[0].NewState.ShouldBe(HostState.Running);
+        agg.Snapshot()[0].HostName.ShouldBe("OtOpcUa-A");
+    }
+
+    [Fact]
+    public void SetTransport_StateTransition_FiresChange()
+    {
+        var agg = new HostStatusAggregator();
+        var fwd = new HostConnectivityForwarder("OtOpcUa-A", agg);
+
+        fwd.SetTransport(HostState.Running);
+        var captured = new List<HostStatusChangedEventArgs>();
+        agg.OnHostStatusChanged += (_, e) => captured.Add(e);
+
+        fwd.SetTransport(HostState.Stopped);
+
+        captured.Count.ShouldBe(1);
+        captured[0].OldState.ShouldBe(HostState.Running);
+        captured[0].NewState.ShouldBe(HostState.Stopped);
+    }
+
+    [Fact]
+    public void SetTransport_RepeatedSameState_DoesNotFire()
+    {
+        var agg = new HostStatusAggregator();
+        var fwd = new HostConnectivityForwarder("OtOpcUa-A", agg);
+
+        fwd.SetTransport(HostState.Running);
+        var captured = new List<HostStatusChangedEventArgs>();
+        agg.OnHostStatusChanged += (_, e) => captured.Add(e);
+
+        fwd.SetTransport(HostState.Running);
+        fwd.SetTransport(HostState.Running);
+        fwd.SetTransport(HostState.Running);
+
+        captured.ShouldBeEmpty();
+    }
+
+    [Fact]
+    public void Constructor_RejectsEmptyClientName()
+    {
+        var agg = new HostStatusAggregator();
+        Should.Throw<ArgumentException>(() => new HostConnectivityForwarder("", agg));
+        Should.Throw<ArgumentException>(() => new HostConnectivityForwarder("   ", agg));
+    }
+
+    [Fact]
+    public void SetTransport_AfterDispose_Throws()
+    {
+        var agg = new HostStatusAggregator();
+        var fwd = new HostConnectivityForwarder("OtOpcUa-A", agg);
+        fwd.Dispose();
+        Should.Throw<ObjectDisposedException>(() => fwd.SetTransport(HostState.Running));
+    }
+}