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.OpcUaClient.IntegrationTests/OpcPlcProfile.cs

@@ -0,0 +1,38 @@
+using ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests;
+
+/// <summary>
+///     Driver-side configuration + well-known opc-plc node identifiers that the smoke
+///     tests address. Node IDs are stable across opc-plc releases — the simulator
+///     guarantees the same <c>ns=3;s=...</c> names shipped since v1.0. If a release
+///     bump breaks these, the fixture's pinned image tag needs a coordinated bump.
+/// </summary>
+public static class OpcPlcProfile
+{
+    /// <summary>opc-plc monotonically-increasing UInt32; ticks once per second under default opts.</summary>
+    public const string StepUp = "ns=3;s=StepUp";
+
+    /// <summary>opc-plc random Int32 node; new value ~every 100ms.</summary>
+    public const string RandomSignedInt32 = "ns=3;s=RandomSignedInt32";
+
+    /// <summary>opc-plc alternating boolean; flips every second.</summary>
+    public const string AlternatingBoolean = "ns=3;s=AlternatingBoolean";
+
+    /// <summary>opc-plc fast uint node — ticks every 100ms. Used for subscription-cadence tests.</summary>
+    public const string FastUInt1 = "ns=3;s=FastUInt1";
+
+    public static OpcUaClientDriverOptions BuildOptions(string endpointUrl) => new()
+    {
+        EndpointUrl = endpointUrl,
+        SecurityPolicy = OpcUaSecurityPolicy.None,
+        SecurityMode = OpcUaSecurityMode.None,
+        AuthType = OpcUaAuthType.Anonymous,
+        // opc-plc auto-accepts client certs (--aa) but we still present one; trust the
+        // server's cert back since the simulator regenerates it each container spin-up
+        // and there's no meaningful chain to validate against.
+        AutoAcceptCertificates = true,
+        Timeout = TimeSpan.FromSeconds(10),
+        SessionTimeout = TimeSpan.FromSeconds(30),
+    };
+}