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.Historian.Wonderware.Tests/ProgramSmokeTests.cs

@@ -0,0 +1,21 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware.Tests;
+
+/// <summary>
+///     Smoke test confirming the sidecar project links and the test project resolves a
+///     ProjectReference to it. Real behavioural tests arrive in PR 3.2 (backend lift) and
+///     PR 3.3 (pipe server). For PR 3.1 we just verify the assembly identity is what the
+///     csproj declares.
+/// </summary>
+public class ProgramSmokeTests
+{
+    [Fact]
+    public void Program_Assembly_HasExpectedName()
+    {
+        typeof(Program).Assembly.GetName().Name
+            .ShouldBe("OtOpcUa.Driver.Historian.Wonderware");
+    }
+}