feat(journal): edit a placed bet

Adds an edit flow to the bet journal — an Edit button per row repurposes the inline
entry form (edit mode), saving via a new UpdatePlacedBetUseCase that preserves the
original placed-at and re-grades the outcome against the result (so a changed
selection/event re-settles). A cancel affordance + an editing banner make the mode
obvious; the submit button switches to "Save changes".

- UpdatePlacedBetUseCase (loads existing for PlacedAt, validates the event, re-grades)
  + IBetJournalService.UpdateAsync + service impl; Journal page edit-mode state +
  per-row Edit button; en/ru resx.
- 3 tests: unknown-bet, unknown-event, and preserve-PlacedAt + re-grade.

src/Marathon.Application/UseCases/UpdatePlacedBetUseCase.cs

@@ -0,0 +1,86 @@
+using Marathon.Application.Abstractions;
+using Marathon.Domain.Entities;
+using Marathon.Domain.Enums;
+using Microsoft.Extensions.Logging;
+using DomainEventId = Marathon.Domain.ValueObjects.EventId;
+
+namespace Marathon.Application.UseCases;
+
+/// <summary>
+/// Edits an existing <see cref="PlacedBet"/> in the journal — selection, stake, or
+/// notes. The original <see cref="PlacedBet.PlacedAt"/> is preserved; the outcome is
+/// re-graded from scratch (so changing the selection or event re-settles correctly).
+/// </summary>
+public sealed class UpdatePlacedBetUseCase
+{
+    private readonly IPlacedBetRepository _bets;
+    private readonly IEventRepository _events;
+    private readonly IResultRepository _results;
+    private readonly ILogger<UpdatePlacedBetUseCase> _logger;
+
+    public UpdatePlacedBetUseCase(
+        IPlacedBetRepository bets,
+        IEventRepository events,
+        IResultRepository results,
+        ILogger<UpdatePlacedBetUseCase> logger)
+    {
+        _bets = bets ?? throw new ArgumentNullException(nameof(bets));
+        _events = events ?? throw new ArgumentNullException(nameof(events));
+        _results = results ?? throw new ArgumentNullException(nameof(results));
+        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+    }
+
+    /// <exception cref="InvalidOperationException">
+    /// The bet id is unknown, or the (possibly changed) event isn't in the store.
+    /// </exception>
+    public async Task<PlacedBet> ExecuteAsync(
+        Guid id,
+        DomainEventId eventId,
+        Bet selection,
+        decimal stake,
+        string? notes,
+        CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(eventId);
+        ArgumentNullException.ThrowIfNull(selection);
+
+        var existing = await _bets.GetAsync(id, ct).ConfigureAwait(false)
+            ?? throw new InvalidOperationException($"Cannot update unknown bet '{id}'.");
+
+        var ev = await _events.GetAsync(eventId, ct).ConfigureAwait(false);
+        if (ev is null)
+        {
+            throw new InvalidOperationException(
+                $"Cannot point a bet at unknown event '{eventId.Value}'. " +
+                "The event must already be present in the scrape store.");
+        }
+
+        // Preserve the original entry time; re-grade from Pending so a changed
+        // selection/event settles against the current result.
+        var toPersist = new PlacedBet(
+            Id: id,
+            EventId: eventId,
+            Selection: selection,
+            Stake: stake,
+            PlacedAt: existing.PlacedAt,
+            Outcome: BetOutcome.Pending,
+            Notes: notes);
+
+        var result = await _results.GetAsync(eventId, ct).ConfigureAwait(false);
+        if (result is not null)
+        {
+            var graded = Marathon.Domain.Betting.BetOutcomeResolver.Resolve(toPersist.Selection, result);
+            if (graded is not null)
+                toPersist = toPersist.WithOutcome(graded.Value);
+        }
+
+        await _bets.UpdateAsync(toPersist, ct).ConfigureAwait(false);
+        await _bets.SaveChangesAsync(ct).ConfigureAwait(false);
+
+        _logger.LogInformation(
+            "UpdatePlacedBetUseCase: updated bet {BetId} on event {EventId} stake={Stake} outcome={Outcome}",
+            id, eventId.Value, stake, toPersist.Outcome);
+
+        return toPersist;
+    }
+}