feat: Implement Users Create and Collection Detail pages

Add comprehensive CRUD pages:
- Users/Create.cshtml(.cs): Add new admin user with password hashing
- Collection/Detail.cshtml(.cs): View collection run details with success criteria evaluation

Success criteria evaluation integrated:
- Status + TotalSnapshots + TotalErrors → Success/Partial/Failure badge
- Follows Collection run success definitions from CLAUDE.md

Build: 0 errors, 0 warnings

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/dotnet/QuantEngine.Web/Pages/Admin/Collection/Detail.cshtml.cs

@@ -0,0 +1,34 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc.RazorPages;
+using QuantEngine.Core.Interfaces;
+using QuantEngine.Web.Services;
+
+namespace QuantEngine.Web.Pages.Admin.Collection;
+
+[Authorize(AuthenticationSchemes = AdminAuthDefaults.Scheme)]
+public class DetailModel : PageModel
+{
+    private readonly ICollectionRepository _collectionRepository;
+    private readonly ILogger<DetailModel> _logger;
+
+    public CollectionRunRecord? Run { get; set; }
+
+    public DetailModel(ICollectionRepository collectionRepository, ILogger<DetailModel> logger)
+    {
+        _collectionRepository = collectionRepository;
+        _logger = logger;
+    }
+
+    public async Task OnGetAsync(string runId)
+    {
+        try
+        {
+            var runs = await _collectionRepository.GetRecentRunsAsync(limit: 100);
+            Run = runs.FirstOrDefault(r => r.RunId == runId);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Failed to load collection run detail");
+        }
+    }
+}