WIP(initial-implementation): parallel batch P2/P3/P5 — code complete, unreviewed

Snapshot of the parallel batch (Phases 2 + 3 + 5) at session pause. Solution does
NOT build cleanly yet — known cross-phase compile issues remain to be resolved
before review. See plans/initial-implementation/PLAN.md "Resume Notes" section
for the exact tomorrow-morning action list.

Phase 2 (Storage):
- Repository interfaces in Marathon.Application/Abstractions
- DateRange, ExportKind, StorageOptions in Marathon.Application/Storage
- EF Core 8 + SQLite (WAL) persistence: 7 entities + configurations + 4 repos
- Hand-written InitialCreate migration (dotnet ef blocked by parallel work)
- ClosedXML ExcelExporter with exact customer-spec wide columns
- PersistenceModule.AddMarathonPersistence DI extension
- Round-trip + export tests (cannot run yet — see cross-phase issues)

Phase 3 (Scraping):
- IOddsScraper, IBetPlacer in Marathon.Application/Abstractions
- ScrapingOptions in Marathon.Infrastructure/Configuration
- MarathonbetScraper with 4 parsers (Upcoming, Live, EventOdds, Results)
- Helpers: ServerTimeProvider, PeriodScopeMapper, OutcomeCodeMapper, MoscowDateParser
- UserAgentRotatorHandler + Polly v8 resilience pipeline
- ScrapingModule.AddMarathonScraping DI extension
- GlobalUsings.cs aliases for EventId / Configuration disambiguation
- Parser tests with trimmed HTML fixtures
- ScrapeResultsAsync interim no-op (Phase 8 will replace via watch-list polling)

Phase 5 (UI shell — killed mid-final-verify, assumed ~95%):
- Marathon.UI populated: MainLayout, App.razor, Pages (Home, Settings),
  Components, Theme (MarathonTheme.cs + Tokens.cs + app.css), Resources
  (SharedResource.{cs,ru.resx,en.resx}), Services (ISettingsWriter), wwwroot
- WPF host: App.xaml(.cs), MainWindow.xaml(.cs), Marathon.Hosts.WpfBlazor.csproj
  with Microsoft.AspNetCore.Components.WebView.Wpf + MudBlazor + Serilog
- appsettings.json + appsettings.Development.json with all sections wired
- bUnit tests: MainLayoutTests, LocaleSwitcherTests, ThemeToggleTests,
  JsonSettingsWriterTests + Support helpers

Cross-phase issues to resolve at next session:
1. Phase 2 repository classes are 'internal' — Phase 3's tests can't reference
   them. Fix: add InternalsVisibleTo to Marathon.Infrastructure.csproj.
2. Phase 5: LocalizationOptions namespace ambiguity (AspNetCore vs Extensions).
3. Phase 5: WpfBlazor Serilog API mismatch.

Reviewer has NOT run on this batch. Move to Phase 4 only after build is green
and a combined parallel-batch reviewer passes.

src/Marathon.UI/Services/UiServicesExtensions.cs

@@ -0,0 +1,54 @@
+using Marathon.Application.Storage;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using MudBlazor.Services;
+
+namespace Marathon.UI.Services;
+
+/// <summary>
+/// DI registration helpers for the Marathon.UI Razor Class Library.
+/// Hosts call <see cref="AddMarathonUi(IServiceCollection, IConfiguration, string)"/>
+/// during startup.
+/// </summary>
+public static class UiServicesExtensions
+{
+    /// <summary>
+    /// Registers MudBlazor services, localization, the theme/locale observable
+    /// state objects, the file-backed settings writer, and binds all
+    /// configuration sections that the Settings page surfaces.
+    /// </summary>
+    /// <param name="services">DI container.</param>
+    /// <param name="configuration">Host configuration root.</param>
+    /// <param name="settingsLocalPath">
+    /// Absolute path to <c>appsettings.Local.json</c>, used by the writer.
+    /// </param>
+    public static IServiceCollection AddMarathonUi(
+        this IServiceCollection services,
+        IConfiguration configuration,
+        string settingsLocalPath)
+    {
+        ArgumentNullException.ThrowIfNull(services);
+        ArgumentNullException.ThrowIfNull(configuration);
+        ArgumentException.ThrowIfNullOrEmpty(settingsLocalPath);
+
+        services.AddMudServices();
+
+        services.AddLocalization(options => options.ResourcesPath = "Resources");
+
+        // Strongly typed options bound to appsettings.json sections.
+        services.Configure<LocalizationOptions>(configuration.GetSection(LocalizationOptions.SectionName));
+        services.Configure<WorkerOptions>(configuration.GetSection(WorkerOptions.SectionName));
+        services.Configure<AnomalyOptions>(configuration.GetSection(AnomalyOptions.SectionName));
+        services.Configure<StorageOptions>(configuration.GetSection(StorageOptions.SectionName));
+        services.Configure<ScrapingSettingsForm>(configuration.GetSection(ScrapingSettingsForm.SectionName));
+
+        // Singletons that drive UI chrome state.
+        services.AddSingleton<ThemeState>();
+        services.AddSingleton<LocaleState>();
+
+        // Settings writer — file path is host-resolved.
+        services.AddSingleton<ISettingsWriter>(_ => new JsonSettingsWriter(settingsLocalPath));
+
+        return services;
+    }
+}