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/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/TracedGalaxyDataWriter.cs

@@ -0,0 +1,54 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Runtime;
+
+/// <summary>
+///     PR 6.1 — Decorator that emits one <see cref="System.Diagnostics.Activity"/> span
+///     per gw write batch. Tags secured-write counts so ops can see the routing-by-
+///     classification split (FreeAccess/Operate vs Tune/Configure) without re-reading
+///     the discovery dictionary.
+/// </summary>
+internal sealed class TracedGalaxyDataWriter(IGalaxyDataWriter inner, string clientName) : IGalaxyDataWriter
+{
+    public async Task<IReadOnlyList<WriteResult>> WriteAsync(
+        IReadOnlyList<WriteRequest> writes,
+        Func<string, SecurityClassification> securityResolver,
+        CancellationToken cancellationToken)
+    {
+        using var activity = GalaxyTelemetry.ActivitySource.StartActivity("galaxy.write");
+        activity?.SetTag("galaxy.client", clientName);
+        activity?.SetTag("galaxy.tag_count", writes.Count);
+
+        if (activity is { IsAllDataRequested: true })
+        {
+            // Counting the secured-write split is cheap (one resolver call per request)
+            // and only happens when a tracing listener is actively recording — keeps the
+            // hot path free when no one's listening.
+            var securedCount = 0;
+            foreach (var w in writes)
+            {
+                var sc = securityResolver(w.FullReference);
+                if (sc is SecurityClassification.Tune
+                    or SecurityClassification.Configure
+                    or SecurityClassification.VerifiedWrite)
+                {
+                    securedCount++;
+                }
+            }
+            activity.SetTag("galaxy.secured_write_count", securedCount);
+        }
+
+        try
+        {
+            var results = await inner.WriteAsync(writes, securityResolver, cancellationToken)
+                .ConfigureAwait(false);
+            activity?.SetTag("galaxy.success_count", results.Count(r => r.StatusCode < 0x80000000u));
+            return results;
+        }
+        catch (Exception ex)
+        {
+            activity.RecordError(ex);
+            throw;
+        }
+    }
+}