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/Core/ZB.MOM.WW.OtOpcUa.Configuration.Tests/SchemaComplianceFixture.cs

@@ -0,0 +1,68 @@
+using Microsoft.Data.SqlClient;
+using Microsoft.EntityFrameworkCore;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Tests;
+
+/// <summary>
+///     Spins up a dedicated test database, applies the EF migrations against it, and exposes a
+///     <see cref="SqlConnection"/> factory. Disposed at collection teardown (drops the DB).
+///     Gated by the <c>OTOPCUA_CONFIG_TEST_SERVER</c> env var so CI runs can opt in explicitly;
+///     local runs default to the dev container on <c>localhost:14330</c>.
+/// </summary>
+public sealed class SchemaComplianceFixture : IDisposable
+{
+    private const string DefaultServer = "localhost,14330";
+    private const string DefaultSaPassword = "OtOpcUaDev_2026!";
+
+    public string DatabaseName { get; }
+    public string ConnectionString { get; }
+
+    public SchemaComplianceFixture()
+    {
+        var server = Environment.GetEnvironmentVariable("OTOPCUA_CONFIG_TEST_SERVER") ?? DefaultServer;
+        var saPassword = Environment.GetEnvironmentVariable("OTOPCUA_CONFIG_TEST_SA_PASSWORD") ?? DefaultSaPassword;
+
+        DatabaseName = $"OtOpcUaConfig_Test_{DateTime.UtcNow:yyyyMMddHHmmss}_{Guid.NewGuid():N}";
+        ConnectionString =
+            $"Server={server};Database={DatabaseName};User Id=sa;Password={saPassword};TrustServerCertificate=True;Encrypt=False;";
+
+        var options = new DbContextOptionsBuilder<OtOpcUaConfigDbContext>()
+            .UseSqlServer(ConnectionString)
+            .Options;
+
+        using var ctx = new OtOpcUaConfigDbContext(options);
+        ctx.Database.Migrate();
+    }
+
+    public SqlConnection OpenConnection()
+    {
+        var conn = new SqlConnection(ConnectionString);
+        conn.Open();
+        return conn;
+    }
+
+    public void Dispose()
+    {
+        var masterConnection =
+            new SqlConnectionStringBuilder(ConnectionString) { InitialCatalog = "master" }.ConnectionString;
+
+        using var conn = new SqlConnection(masterConnection);
+        conn.Open();
+
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = $@"
+IF DB_ID(N'{DatabaseName}') IS NOT NULL
+BEGIN
+    ALTER DATABASE [{DatabaseName}] SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
+    DROP DATABASE [{DatabaseName}];
+END";
+        cmd.ExecuteNonQuery();
+    }
+}
+
+[CollectionDefinition(nameof(SchemaComplianceCollection))]
+public sealed class SchemaComplianceCollection : ICollectionFixture<SchemaComplianceFixture>
+{
+}