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.

tests/Marathon.UI.Tests/Support/MarathonTestContext.cs

@@ -0,0 +1,40 @@
+using Bunit;
+using Marathon.UI.Resources;
+using Marathon.UI.Services;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Localization;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+using MudBlazor.Services;
+
+namespace Marathon.UI.Tests.Support;
+
+/// <summary>
+/// Shared bUnit <see cref="TestContext"/> with the Marathon.UI services
+/// pre-registered: localizer, theme + locale state, in-memory settings writer,
+/// MudBlazor services, and a no-op logger.
+/// </summary>
+public abstract class MarathonTestContext : TestContext
+{
+    protected TestSettingsWriter Writer { get; } = new();
+    protected ThemeState Theme { get; } = new();
+    protected LocaleState Locale { get; } = new();
+
+    protected MarathonTestContext()
+    {
+        Services.AddSingleton(Writer);
+        Services.AddSingleton<ISettingsWriter>(Writer);
+        Services.AddSingleton(Theme);
+        Services.AddSingleton(Locale);
+
+        Services.AddSingleton(typeof(IStringLocalizer<>), typeof(TestLocalizer<>));
+        Services.AddSingleton(typeof(ILogger<>), typeof(NullLogger<>));
+        Services.AddLogging();
+
+        Services.AddMudServices();
+
+        // bUnit defaults JS interop to Strict; loosen so MudBlazor's interop
+        // calls don't blow up tests that aren't asserting on JS-driven UI.
+        JSInterop.Mode = JSRuntimeMode.Loose;
+    }
+}