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/Server/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/TestAuthHandler.cs

@@ -0,0 +1,34 @@
+using System.Security.Claims;
+using System.Text.Encodings.Web;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.E2ETests;
+
+/// <summary>
+///     Stamps every request with a FleetAdmin principal so E2E tests can hit
+///     authenticated Razor pages without the LDAP login flow. Registered as the
+///     default authentication scheme by <see cref="AdminWebAppFactory"/>.
+/// </summary>
+public sealed class TestAuthHandler(
+    IOptionsMonitor<AuthenticationSchemeOptions> options,
+    ILoggerFactory logger,
+    UrlEncoder encoder)
+    : AuthenticationHandler<AuthenticationSchemeOptions>(options, logger, encoder)
+{
+    public const string SchemeName = "Test";
+
+    protected override Task<AuthenticateResult> HandleAuthenticateAsync()
+    {
+        var claims = new[]
+        {
+            new Claim(ClaimTypes.Name, "e2e-test-user"),
+            new Claim(ClaimTypes.Role, AdminRoles.FleetAdmin),
+        };
+        var identity = new ClaimsIdentity(claims, SchemeName);
+        var ticket = new AuthenticationTicket(new ClaimsPrincipal(identity), SchemeName);
+        return Task.FromResult(AuthenticateResult.Success(ticket));
+    }
+}