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/Client/ZB.MOM.WW.OtOpcUa.Client.UI/Helpers/StatusCodeFormatter.cs

@@ -0,0 +1,36 @@
+using Opc.Ua;
+
+namespace ZB.MOM.WW.OtOpcUa.Client.UI.Helpers;
+
+/// <summary>
+/// Formats OPC UA status codes as "0xHEX (description)".
+/// </summary>
+internal static class StatusCodeFormatter
+{
+    public static string Format(StatusCode statusCode)
+    {
+        var code = statusCode.Code;
+        var hex = $"0x{code:X8}";
+
+        // Try the SDK's browse name lookup first
+        var name = StatusCodes.GetBrowseName(code);
+        if (!string.IsNullOrEmpty(name))
+            return $"{hex} ({name})";
+
+        // Try masking to just the main code (top 16 bits) for sub-status codes
+        var mainCode = code & 0xFFFF0000;
+        if (mainCode != code)
+        {
+            name = StatusCodes.GetBrowseName(mainCode);
+            if (!string.IsNullOrEmpty(name))
+                return $"{hex} ({name})";
+        }
+
+        // Fallback to severity category
+        if (StatusCode.IsGood(statusCode))
+            return $"{hex} (Good)";
+        if (StatusCode.IsBad(statusCode))
+            return $"{hex} (Bad)";
+        return $"{hex} (Uncertain)";
+    }
+}