feat(my-bets): personal bet journal with CLV tracking

Adds a manual bet-tracking journal that turns the analyzer into an actual
bet tracker. Users record wagers; the journal auto-grades them when event
results land and computes per-bet Closing-Line-Value against the latest
pre-match snapshot — the strongest long-run indicator of betting skill.

Domain:
- PlacedBet entity (reuses Bet vocabulary for Scope/Type/Side/Value/Rate)
  with stake, placed-at, outcome, and notes. Derived GrossReturn / NetProfit.
- BetOutcome enum (Pending / Won / Lost / Void).
- BetOutcomeResolver: pure function grading any Match-scope bet against an
  EventResult. Handles 1X2, draws, handicap (incl. push), and totals.
  Period-scope bets stay manual since EventResult only carries full-time.

Application:
- IPlacedBetRepository abstraction.
- ClosingLineValueCalculator: pure CLV math (implied-probability delta) +
  snapshot-matching predicate by Scope/Type/Side/Value.
- BetJournalReport + BetJournalStats records.
- Four use cases: Record / ResolvePending / BuildReport / Delete.
- New ISnapshotRepository.GetLatestPreMatchAsync pushes the closing-line
  pick into a single SQLite query rather than materialising the 30-day
  window in memory per event.
- ROI turnover excludes Void stakes — pushes are not real turnover and
  including them would dilute the user's edge.

Infrastructure:
- PlacedBetEntity / Configuration / Repository / Mapping helpers.
- 20260516 migration adding the PlacedBets table with EventCode and
  Outcome indices. Intentionally NO foreign key to Events — the journal
  is user data and must survive snapshot-retention pruning. Covered by an
  explicit round-trip test.

UI:
- Pages/MyBets/Journal.razor: hero header, 4-card KPI strip (ROI / strike
  rate / avg CLV / net profit, tinted by tone), inline add-bet form with
  the same invariants as the Bet record, drill-down table with per-row
  outcome pills, CLV percentage-points column, P&L, notes underline, and
  inline-confirm delete. RU + EN i18n.
- Nav entry under Analysis.

Tests: +55 across Domain / Application / Infrastructure (resolver math
including handicap push and total push boundaries, PlacedBet invariants
and derived properties, CLV math + null-handling, four use cases under
NSubstitute, EF round-trip including survives-event-deletion). All 379
tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Marathon.Infrastructure/Persistence/Mapping.cs

@@ -158,6 +158,51 @@ internal static class Mapping
             NameRu: entity.NameRu,
             NameEn: entity.NameEn);
 
+    // ─── PlacedBet ────────────────────────────────────────────────────────────
+
+    public static PlacedBetEntity ToEntity(PlacedBet domain) =>
+        new()
+        {
+            Id = domain.Id.ToString(),
+            EventCode = domain.EventId.Value,
+            Scope = domain.Selection.Scope is MatchScope ? ScopeMatch : ScopePeriod,
+            PeriodNumber = domain.Selection.Scope is PeriodScope ps ? ps.Number : null,
+            Type = (int)domain.Selection.Type,
+            Side = (int)domain.Selection.Side,
+            Value = domain.Selection.Value?.Value,
+            Rate = domain.Selection.Rate.Value,
+            Stake = domain.Stake,
+            PlacedAt = domain.PlacedAt.ToString("O"),
+            Outcome = (int)domain.Outcome,
+            Notes = domain.Notes,
+        };
+
+    public static PlacedBet ToDomain(PlacedBetEntity entity)
+    {
+        var scope = entity.Scope switch
+        {
+            ScopeMatch  => (BetScope)MatchScope.Instance,
+            ScopePeriod => new PeriodScope(entity.PeriodNumber!.Value),
+            _ => throw new InvalidOperationException(
+                $"Unknown BetScope discriminator: {entity.Scope}"),
+        };
+
+        var value = entity.Value.HasValue ? new OddsValue(entity.Value.Value) : null;
+        var rate = new OddsRate(entity.Rate);
+        var type = (BetType)entity.Type;
+        var side = (Side)entity.Side;
+        var selection = new Bet(scope, type, side, value, rate);
+
+        return new PlacedBet(
+            Id: Guid.Parse(entity.Id),
+            EventId: new EventId(entity.EventCode),
+            Selection: selection,
+            Stake: entity.Stake,
+            PlacedAt: DateTimeOffset.Parse(entity.PlacedAt, CultureInfo.InvariantCulture, RoundtripStyles),
+            Outcome: (BetOutcome)entity.Outcome,
+            Notes: entity.Notes);
+    }
+
     // ─── League ───────────────────────────────────────────────────────────────
 
     public static LeagueEntity ToEntity(League domain) =>