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.Infrastructure/Persistence/Configurations/EventConfiguration.cs

@@ -0,0 +1,42 @@
+using Marathon.Infrastructure.Persistence.Entities;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace Marathon.Infrastructure.Persistence.Configurations;
+
+internal sealed class EventConfiguration : IEntityTypeConfiguration<EventEntity>
+{
+    public void Configure(EntityTypeBuilder<EventEntity> builder)
+    {
+        builder.ToTable("Events");
+
+        builder.HasKey(e => e.EventCode);
+        builder.Property(e => e.EventCode).HasColumnType("TEXT").IsRequired();
+        builder.Property(e => e.SportCode).HasColumnType("INTEGER").IsRequired();
+        builder.Property(e => e.CountryCode).HasColumnType("TEXT").IsRequired();
+        builder.Property(e => e.LeagueId).HasColumnType("TEXT").IsRequired();
+        builder.Property(e => e.Category).HasColumnType("TEXT").HasDefaultValue(string.Empty);
+        builder.Property(e => e.ScheduledAt).HasColumnType("TEXT").IsRequired();
+        builder.Property(e => e.Side1Name).HasColumnType("TEXT").IsRequired();
+        builder.Property(e => e.Side2Name).HasColumnType("TEXT").IsRequired();
+
+        // Index for date-range queries and sport filtering
+        builder.HasIndex(e => new { e.SportCode, e.ScheduledAt }).HasDatabaseName("IX_Events_SportCode_ScheduledAt");
+        builder.HasIndex(e => e.ScheduledAt).HasDatabaseName("IX_Events_ScheduledAt");
+
+        builder.HasMany(e => e.Snapshots)
+            .WithOne(s => s.Event)
+            .HasForeignKey(s => s.EventCode)
+            .OnDelete(DeleteBehavior.Cascade);
+
+        builder.HasOne(e => e.Result)
+            .WithOne(r => r.Event)
+            .HasForeignKey<EventResultEntity>(r => r.EventCode)
+            .OnDelete(DeleteBehavior.Cascade);
+
+        builder.HasMany(e => e.Anomalies)
+            .WithOne(a => a.Event)
+            .HasForeignKey(a => a.EventCode)
+            .OnDelete(DeleteBehavior.Cascade);
+    }
+}