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.Shared/Helpers/FailoverUrlParser.cs

@@ -0,0 +1,52 @@
+namespace ZB.MOM.WW.OtOpcUa.Client.Shared.Helpers;
+
+/// <summary>
+///     Parses and normalizes failover URL sets for redundant OPC UA connections.
+/// </summary>
+public static class FailoverUrlParser
+{
+    /// <summary>
+    ///     Parses a comma-separated failover URL string, prepending the primary URL.
+    ///     Trims whitespace and deduplicates.
+    /// </summary>
+    /// <param name="primaryUrl">The primary endpoint URL.</param>
+    /// <param name="failoverCsv">Optional comma-separated failover URLs.</param>
+    /// <returns>An array with the primary URL first, followed by unique failover URLs.</returns>
+    public static string[] Parse(string primaryUrl, string? failoverCsv)
+    {
+        if (string.IsNullOrWhiteSpace(failoverCsv))
+            return [primaryUrl];
+
+        var urls = new List<string> { primaryUrl };
+        foreach (var url in failoverCsv.Split(',', StringSplitOptions.RemoveEmptyEntries))
+        {
+            var trimmed = url.Trim();
+            if (!string.IsNullOrEmpty(trimmed) && !urls.Contains(trimmed, StringComparer.OrdinalIgnoreCase))
+                urls.Add(trimmed);
+        }
+
+        return urls.ToArray();
+    }
+
+    /// <summary>
+    ///     Builds a failover URL set from the primary URL and an optional array of failover URLs.
+    /// </summary>
+    /// <param name="primaryUrl">The primary endpoint URL.</param>
+    /// <param name="failoverUrls">Optional failover URLs.</param>
+    /// <returns>An array with the primary URL first, followed by unique failover URLs.</returns>
+    public static string[] Parse(string primaryUrl, string[]? failoverUrls)
+    {
+        if (failoverUrls == null || failoverUrls.Length == 0)
+            return [primaryUrl];
+
+        var urls = new List<string> { primaryUrl };
+        foreach (var url in failoverUrls)
+        {
+            var trimmed = url?.Trim();
+            if (!string.IsNullOrEmpty(trimmed) && !urls.Contains(trimmed, StringComparer.OrdinalIgnoreCase))
+                urls.Add(trimmed);
+        }
+
+        return urls.ToArray();
+    }
+}