perf: batch repository reads, index snapshots, centralize date encoding

- Add IEventRepository/IResultRepository.GetManyAsync to kill N+1 lookups at
  6 sites (backtest, outcome eval, both bet-journal paths, anomaly browsing,
  results selection); guarded by a Received(1).GetManyAsync test.
- Add EventRepository.QueryAsync to push date+sport filtering to SQL (was
  load-whole-range-then-filter); search/sort stay in-memory for Cyrillic order.
- Add AnomalyRepository.CountSinceAsync (unread badge) + ListByDateRangeAsync
  (feed date filter); add Event/Snapshot count methods for the dashboard.
- Add composite indexes IX_Snapshots_EventCode_CapturedAt and
  _EventCode_Source_CapturedAt via a new migration + model snapshot.
- Introduce SqliteDateText as the single source of the O-format date encoding
  shared by Mapping (read/write) and the repositories' range predicates.
- Fix LiveOddsPoller cadence drift (budget sleep against cycle time); make
  DetectAnomalies dedup O(1) per event; add Event.Title to dedup the title join.

Tests adapted to the batched GetManyAsync via a TestFixtures bridge.

tests/Marathon.Application.Tests/UseCases/BuildBetJournalReportUseCaseTests.cs

@@ -19,6 +19,12 @@ public sealed class BuildBetJournalReportUseCaseTests
     private readonly IEventRepository _events = Substitute.For<IEventRepository>();
     private readonly ISnapshotRepository _snapshots = Substitute.For<ISnapshotRepository>();
 
+    public BuildBetJournalReportUseCaseTests()
+    {
+        // Use case batches event loads via GetManyAsync; route through per-id stubs.
+        TestFixtures.BridgeGetMany(_events);
+    }
+
     private BuildBetJournalReportUseCase CreateSut() =>
         new(_bets, _events, _snapshots, NullLogger<BuildBetJournalReportUseCase>.Instance);
 

tests/Marathon.Application.Tests/UseCases/EvaluateAnomalyOutcomesUseCaseTests.cs

@@ -22,6 +22,14 @@ public sealed class EvaluateAnomalyOutcomesUseCaseTests
     private readonly IEventRepository _events = Substitute.For<IEventRepository>();
     private readonly IResultRepository _results = Substitute.For<IResultRepository>();
 
+    public EvaluateAnomalyOutcomesUseCaseTests()
+    {
+        // Use cases batch event/result loads via GetManyAsync; route those through
+        // the per-id GetAsync stubs each test already configures.
+        TestFixtures.BridgeGetMany(_events);
+        TestFixtures.BridgeGetMany(_results);
+    }
+
     private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
     private static readonly DateTimeOffset BaseTime =
         new(2026, 5, 10, 18, 0, 0, MoscowOffset);
@@ -287,6 +295,36 @@ public sealed class EvaluateAnomalyOutcomesUseCaseTests
         report.EventTitles[id].Should().Be("Team A vs Team B");
     }
 
+    [Fact]
+    public async Task Should_BatchEventAndResultLoads_InsteadOfPerIdGetAsync()
+    {
+        // Regression guard for the N+1 fix: the use case must resolve events/results
+        // via the batched GetManyAsync, never the per-id GetAsync in a loop. We stub
+        // GetManyAsync directly (overriding the constructor bridge) so DidNotReceive()
+        // on GetAsync is meaningful.
+        var id1 = new EventId("11111111");
+        var id2 = new EventId("22222222");
+
+        _anomalies.ListAsync(Arg.Any<CancellationToken>())
+            .Returns(new[] { MakeAnomaly(id1, 0.55m), MakeAnomaly(id2, 0.55m) }.ToList().AsReadOnly());
+
+        _events.GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>())
+            .Returns(new Dictionary<EventId, Event> { [id1] = MakeEvent(id1, 11), [id2] = MakeEvent(id2, 6) });
+        _results.GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>())
+            .Returns(new Dictionary<EventId, EventResult>());
+
+        await CreateSut().ExecuteAsync(CancellationToken.None);
+
+        await _events.Received(1)
+            .GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>());
+        await _events.DidNotReceive()
+            .GetAsync(Arg.Any<EventId>(), Arg.Any<CancellationToken>());
+        await _results.Received(1)
+            .GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>());
+        await _results.DidNotReceive()
+            .GetAsync(Arg.Any<EventId>(), Arg.Any<CancellationToken>());
+    }
+
     [Fact]
     public async Task Should_HandleMissingEvent_By_OmittingFromSportBuckets()
     {

tests/Marathon.Application.Tests/UseCases/PullResultsUseCaseTests.cs

@@ -17,6 +17,13 @@ public sealed class PullResultsUseCaseTests
     private readonly IEventRepository _eventRepo = Substitute.For<IEventRepository>();
     private readonly IResultRepository _resultRepo = Substitute.For<IResultRepository>();
 
+    public PullResultsUseCaseTests()
+    {
+        // Selection-mode candidate resolution now batches via GetManyAsync; route
+        // it through the per-id GetAsync stubs each test configures.
+        TestFixtures.BridgeGetMany(_eventRepo);
+    }
+
     private static readonly DateRange AnyRange = new(
         DateTimeOffset.UtcNow.AddDays(-1),
         DateTimeOffset.UtcNow);

tests/Marathon.Application.Tests/UseCases/RunBacktestUseCaseTests.cs

@@ -25,6 +25,13 @@ public sealed class RunBacktestUseCaseTests
     private readonly IEventRepository _events = Substitute.For<IEventRepository>();
     private readonly IResultRepository _results = Substitute.For<IResultRepository>();
 
+    public RunBacktestUseCaseTests()
+    {
+        // Use case batches event/result loads via GetManyAsync; route through per-id stubs.
+        TestFixtures.BridgeGetMany(_events);
+        TestFixtures.BridgeGetMany(_results);
+    }
+
     private RunBacktestUseCase CreateSut() =>
         new(_anomalies, _events, _results, NullLogger<RunBacktestUseCase>.Instance);
 

tests/Marathon.Application.Tests/UseCases/TestFixtures.cs

@@ -1,8 +1,10 @@
+using Marathon.Application.Abstractions;
 using Marathon.Application.Configuration;
 using Marathon.Domain.Entities;
 using Marathon.Domain.Enums;
 using Marathon.Domain.ValueObjects;
 using Microsoft.Extensions.Options;
+using NSubstitute;
 
 namespace Marathon.Application.Tests.UseCases;
 
@@ -13,6 +15,45 @@ internal static class TestFixtures
 {
     private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
 
+    /// <summary>
+    /// Bridges the legacy per-id <c>GetAsync</c> stubs to the batched
+    /// <c>GetManyAsync</c> the use cases now call: each requested id is resolved
+    /// through whatever <c>GetAsync</c> was configured to return for it. Lets the
+    /// existing per-id <c>.Returns(...)</c> setups keep working unchanged.
+    /// </summary>
+    public static void BridgeGetMany(IEventRepository events)
+    {
+        events.GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>())
+            .Returns(ci =>
+            {
+                var ids = ci.Arg<IReadOnlyCollection<EventId>>();
+                var dict = new Dictionary<EventId, Event>();
+                foreach (var id in ids.Distinct())
+                {
+                    var ev = events.GetAsync(id, CancellationToken.None).GetAwaiter().GetResult();
+                    if (ev is not null) dict[id] = ev;
+                }
+                return (IReadOnlyDictionary<EventId, Event>)dict;
+            });
+    }
+
+    /// <inheritdoc cref="BridgeGetMany(IEventRepository)"/>
+    public static void BridgeGetMany(IResultRepository results)
+    {
+        results.GetManyAsync(Arg.Any<IReadOnlyCollection<EventId>>(), Arg.Any<CancellationToken>())
+            .Returns(ci =>
+            {
+                var ids = ci.Arg<IReadOnlyCollection<EventId>>();
+                var dict = new Dictionary<EventId, EventResult>();
+                foreach (var id in ids.Distinct())
+                {
+                    var r = results.GetAsync(id, CancellationToken.None).GetAwaiter().GetResult();
+                    if (r is not null) dict[id] = r;
+                }
+                return (IReadOnlyDictionary<EventId, EventResult>)dict;
+            });
+    }
+
     /// <summary>Creates a minimal valid <see cref="Event"/> with the given event ID string.</summary>
     public static Event MakeEvent(string eventIdValue = "12345678")
     {