feat(phase-8-backend): per-event results harvesting + EventPath plumbing

Implements Phase 8 Amendment 1: marathonbet.by has no public results archive
endpoint, so results must be harvested per-event by re-fetching the event
detail page until eventJsonInfo.matchIsComplete=true.

Backend changes:

* IOddsScraper:
  - ScrapeResultsAsync(DateRange) replaced with ScrapeEventResultAsync(Event)
    returning a nullable EventResult — null when match still in progress.
  - ScrapeEventOddsAsync now takes the full Event (so EventPath drives URL
    construction) instead of bare EventId.
  - New ScrapeLiveAsync() for the /su/live listing.

* Domain:
  - Event gains EventPath (nullable string) — the data-event-path attribute
    captured during scraping; required for reliable URL construction.

* Infrastructure:
  - New migration 20260506000000_AddEventPath adds the column.
  - EventEntity / EventConfiguration / Mapping / model-snapshot updated.
  - MarathonbetScraper: new ScrapeLiveAsync + ScrapeEventResultAsync; URL
    builder prefers EventPath, falls back to numeric ID for legacy rows.
  - EventListingParserBase extracts data-event-path on every listing row.

* Application:
  - PullResultsUseCase: branches on selection vs date-range, emits IProgress<
    PullResultsProgress>, returns ResultLoadOutcome (Loaded / AlreadyLoaded /
    NotYetComplete / Failed); idempotent (skips events whose result already
    exists).
  - PullLiveOddsUseCase now drives off the live listing (auto-discovers
    events that go live without ever appearing in the upcoming list) and
    backfills EventPath on legacy rows.
  - PullUpcomingEventsUseCase wires EventPath on persisted events.

* Workers: UpcomingEventsPoller updates persistence path accordingly.

* Tests: 17 net-new tests across Application + Infrastructure + Domain;
  all 293 still pass.

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

@@ -30,8 +30,8 @@ public sealed class PullUpcomingEventsUseCaseTests
 
         _scraper.ScrapeUpcomingAsync(null, Arg.Any<CancellationToken>()).Returns(events);
         _eventRepo.GetAsync(Arg.Any<EventId>(), Arg.Any<CancellationToken>()).Returns((Event?)null);
-        _scraper.ScrapeEventOddsAsync(Arg.Any<EventId>(), OddsSource.PreMatch, Arg.Any<CancellationToken>())
-            .Returns(ci => TestFixtures.MakeSnapshot(ci.Arg<EventId>()));
+        _scraper.ScrapeEventOddsAsync(Arg.Any<Event>(), OddsSource.PreMatch, Arg.Any<CancellationToken>())
+            .Returns(ci => TestFixtures.MakeSnapshot(ci.Arg<Event>().Id));
 
         var sut = CreateSut();
 
@@ -63,8 +63,8 @@ public sealed class PullUpcomingEventsUseCaseTests
         _eventRepo.GetAsync(ev2.Id, Arg.Any<CancellationToken>()).Returns((Event?)null);
         _eventRepo.GetAsync(ev3.Id, Arg.Any<CancellationToken>()).Returns((Event?)null);
 
-        _scraper.ScrapeEventOddsAsync(Arg.Any<EventId>(), OddsSource.PreMatch, Arg.Any<CancellationToken>())
-            .Returns(ci => TestFixtures.MakeSnapshot(ci.Arg<EventId>()));
+        _scraper.ScrapeEventOddsAsync(Arg.Any<Event>(), OddsSource.PreMatch, Arg.Any<CancellationToken>())
+            .Returns(ci => TestFixtures.MakeSnapshot(ci.Arg<Event>().Id));
 
         var sut = CreateSut();
 
@@ -91,9 +91,11 @@ public sealed class PullUpcomingEventsUseCaseTests
         _scraper.ScrapeUpcomingAsync(null, Arg.Any<CancellationToken>()).Returns(events);
         _eventRepo.GetAsync(Arg.Any<EventId>(), Arg.Any<CancellationToken>()).Returns((Event?)null);
 
-        _scraper.ScrapeEventOddsAsync(ev1.Id, OddsSource.PreMatch, Arg.Any<CancellationToken>())
+        _scraper.ScrapeEventOddsAsync(
+                Arg.Is<Event>(e => e.Id == ev1.Id), OddsSource.PreMatch, Arg.Any<CancellationToken>())
             .ThrowsAsync(new HttpRequestException("site down"));
-        _scraper.ScrapeEventOddsAsync(ev2.Id, OddsSource.PreMatch, Arg.Any<CancellationToken>())
+        _scraper.ScrapeEventOddsAsync(
+                Arg.Is<Event>(e => e.Id == ev2.Id), OddsSource.PreMatch, Arg.Any<CancellationToken>())
             .Returns(TestFixtures.MakeSnapshot(ev2.Id));
 
         var sut = CreateSut();