Task #242 partial — UnsTab interactive E2E test bodies + harness upgrades (tests Skip-guarded pending blazor.web.js asset plumbing)

Carries the interactive drag-drop + 409 concurrent-edit test bodies (full Playwright
flows against the real @ondragstart/@ondragover/@ondrop handlers + modal + EF state
round-trip), plus several harness upgrades that push the in-process
WebApplication-based fixture closer to a working Blazor Server circuit. The
interactive tests are marked [Fact(Skip=...)] pending resolution of one remaining
blocker documented in the class docstring.

Harness upgrades (AdminWebAppFactory):
  - Environment set to Development so 500s surface exception stacks (rather than
    the generic error page) during future diagnosis.
  - ContentRootPath pointed at the Admin assembly dir so wwwroot + manifest files
    resolve.
  - Wired SignalR hubs (/hubs/fleet, /hubs/alerts) so ClusterDetail's HubConnection
    negotiation no longer 500s at first render.
  - Services property exposed so tests can open scoped DI contexts against the
    running host (scheduled peer-edit simulation, post-commit state assertion).

Remaining blocker (reason for Skip):
  /_framework/blazor.web.js returns HTTP 200 with a zero-byte body. The asset's
  route is declared in OtOpcUa.Admin.staticwebassets.endpoints.json, but the
  underlying file is shipped by the framework NuGet package
  (Microsoft.AspNetCore.App.Internal.Assets/_framework/blazor.web.js) rather than
  copied into the Admin wwwroot. MapStaticAssets can't resolve it without wiring
  a composite FileProvider or the WebRootPath machinery. Three viable next-session
  approaches listed in the class docstring:
    (a) Composite FileProvider mapping /_framework/* → NuGet cache.
    (b) Subprocess harness spawning real dotnet run of Admin project with an
        InMemory-DB override (closest to production composition).
    (c) MSBuild ItemGroup in the test csproj that copies framework files into the
        test output + ContentRoot=test assembly dir with UseStaticFiles.

Scaffolding smoke test (Admin_host_serves_HTTP_via_Playwright_scaffolding) stays
green unchanged.

Suite state: 1 passed, 2 skipped, 0 failed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/AdminWebAppFactory.cs

@@ -5,6 +5,7 @@ using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
+using ZB.MOM.WW.OtOpcUa.Admin.Hubs;
 using ZB.MOM.WW.OtOpcUa.Configuration;
 using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
 using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
@@ -32,13 +33,36 @@ public sealed class AdminWebAppFactory : IAsyncDisposable
     public long SeededGenerationId { get; private set; }
     public string SeededClusterId { get; } = "e2e-cluster";
 
+    /// <summary>
+    ///     Root service provider of the running host. Tests use this to create scopes that
+    ///     share the InMemory DB with the Blazor-rendered page — e.g. to assert post-commit
+    ///     state, or to simulate a concurrent peer edit that bumps the DraftRevisionToken
+    ///     between preview-open and Confirm-click.
+    /// </summary>
+    public IServiceProvider Services => _app?.Services
+        ?? throw new InvalidOperationException("AdminWebAppFactory: StartAsync has not been called");
+
     public async Task StartAsync()
     {
         var port = GetFreeTcpPort();
         BaseUrl = $"http://127.0.0.1:{port}";
 
-        var builder = WebApplication.CreateBuilder(Array.Empty<string>());
+        // Point the content root at the Admin project's build output so wwwroot/ (app.css,
+        // site CSS, icons) + the Blazor framework assets served from the Admin assembly
+        // resolve. Without this the default content root is the test project's bin dir and
+        // blazor.web.js + app.css return 404, which keeps the interactive circuit from
+        // booting at all.
+        var adminAssemblyDir = System.IO.Path.GetDirectoryName(
+            typeof(Admin.Components.App).Assembly.Location)!;
+        var builder = WebApplication.CreateBuilder(new WebApplicationOptions
+        {
+            ContentRootPath = adminAssemblyDir,
+        });
         builder.WebHost.UseUrls(BaseUrl);
+        // E2E host runs in Development so unhandled exceptions during Blazor render surface
+        // as visible 500s with stacks the test can capture — prod-style generic errors make
+        // diagnosis of circuit / DI misconfig effectively impossible.
+        builder.Environment.EnvironmentName = Microsoft.Extensions.Hosting.Environments.Development;
 
         // --- Mirror the Admin composition in Program.cs, but with the InMemory DB + test
         // auth swaps instead of SQL Server + LDAP cookie auth.
@@ -72,6 +96,12 @@ public sealed class AdminWebAppFactory : IAsyncDisposable
         _app.UseAuthorization();
         _app.UseAntiforgery();
         _app.MapRazorComponents<Admin.Components.App>().AddInteractiveServerRenderMode();
+        // The ClusterDetail + other pages connect SignalR hubs at render time — the
+        // endpoints must exist or the Blazor circuit surfaces a 500 on first interactive
+        // step. No background pollers (FleetStatusPoller etc.) are registered so the hubs
+        // stay quiet until something pushes through IHubContext, which the E2E tests don't.
+        _app.MapHub<FleetStatusHub>("/hubs/fleet");
+        _app.MapHub<AlertHub>("/hubs/alerts");
 
         // Seed the draft BEFORE starting the host so Playwright sees a ready page on first nav.
         using (var scope = _app.Services.CreateScope())