refactor: hoist Moscow offset + sport labels into shared helpers (HIGH)

* New Marathon.Domain.ValueObjects.MoscowTime with Offset, Now, and
  EndOfMoscowDay(DateOnly) — replaces ~15 inline TimeSpan.FromHours(3)
  literals across Domain/Application/Infrastructure/UI.
* New Marathon.UI.Services.SportLabels.Resolve(IStringLocalizer, int) —
  replaces 6 near-identical SportLabel switch bodies in EventListShell,
  Events/Detail, Anomalies/AnomalyFeed, Results/ResultsList,
  Results/ResultsLoader, and AnomalyCard. Single source of truth for the
  6/11/22723/43658 sport-code mapping. Pages keep a one-liner wrapper so
  the call sites stay terse.

src/Marathon.Application/UseCases/DetectAnomaliesUseCase.cs

@@ -2,6 +2,7 @@ using Marathon.Application.Abstractions;
 using Marathon.Application.Configuration;
 using Marathon.Domain.AnomalyDetection;
 using Marathon.Domain.Entities;
+using Marathon.Domain.ValueObjects;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 
@@ -24,7 +25,6 @@ namespace Marathon.Application.UseCases;
 /// </remarks>
 public sealed class DetectAnomaliesUseCase
 {
-    private static readonly TimeSpan MoscowOffset     = TimeSpan.FromHours(3);
     private static readonly TimeSpan SnapshotLookback = TimeSpan.FromHours(24);
 
     // Dedup window: two anomalies for the same event within this window are considered duplicates.
@@ -67,7 +67,7 @@ public sealed class DetectAnomaliesUseCase
         var events = await _eventRepo.ListAsync(ct);
         int newAnomalyCount = 0;
 
-        var now  = DateTimeOffset.UtcNow.ToOffset(MoscowOffset);
+        var now  = MoscowTime.Now;
         var from = now - SnapshotLookback;
 
         // Hoisted outside the per-event loop: load existing anomalies ONCE per cycle

src/Marathon.Domain/AnomalyDetection/AnomalyDetector.cs

@@ -27,8 +27,6 @@ namespace Marathon.Domain.AnomalyDetection;
 /// </summary>
 public sealed class AnomalyDetector
 {
-    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
-
     private readonly int _suspensionGapSeconds;
     private readonly decimal _oddsFlipThreshold;
     private readonly int _minSnapshotCount;
@@ -156,7 +154,7 @@ public sealed class AnomalyDetector
         return new Anomaly(
             Id:          Guid.NewGuid(),
             EventId:     eventId,
-            DetectedAt:  DateTimeOffset.UtcNow.ToOffset(MoscowOffset),
+            DetectedAt:  MoscowTime.Now,
             Kind:        AnomalyKind.SuspensionFlip,
             Score:       clampedScore,
             EvidenceJson: evidenceJson);

src/Marathon.Domain/Entities/Event.cs

@@ -21,8 +21,6 @@ public sealed record Event(
     string Side1Name,
     string Side2Name)
 {
-    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
-
     public EventId Id { get; } = Id ?? throw new ArgumentNullException(nameof(Id));
 
     public SportCode Sport { get; } = Sport ?? throw new ArgumentNullException(nameof(Sport));
@@ -37,7 +35,7 @@ public sealed record Event(
 
     public string Category { get; } = Category ?? string.Empty;
 
-    public DateTimeOffset ScheduledAt { get; } = ScheduledAt.Offset == MoscowOffset
+    public DateTimeOffset ScheduledAt { get; } = ScheduledAt.Offset == MoscowTime.Offset
         ? ScheduledAt
         : throw new ArgumentException(
             $"ScheduledAt must be in Europe/Moscow time (UTC+03:00). " +

src/Marathon.Domain/ValueObjects/MoscowTime.cs

@@ -0,0 +1,32 @@
+namespace Marathon.Domain.ValueObjects;
+
+/// <summary>
+/// Single source of truth for the Moscow timezone offset.
+/// </summary>
+/// <remarks>
+/// <para>
+/// marathonbet.by serves all timestamps in Moscow time (UTC+3) and the domain
+/// invariant on <see cref="Marathon.Domain.Entities.Event.ScheduledAt"/>
+/// rejects any other offset. Code that constructs <see cref="DateTimeOffset"/>
+/// values for events, results, snapshots, or test fixtures MUST use this
+/// constant rather than re-deriving <c>TimeSpan.FromHours(3)</c>.
+/// </para>
+/// </remarks>
+public static class MoscowTime
+{
+    /// <summary>The Moscow time offset (UTC+3).</summary>
+    public static readonly TimeSpan Offset = TimeSpan.FromHours(3);
+
+    /// <summary>Current Moscow time.</summary>
+    public static DateTimeOffset Now => DateTimeOffset.UtcNow.ToOffset(Offset);
+
+    /// <summary>
+    /// Returns the inclusive end-of-day for the given Moscow date — i.e.,
+    /// the moment one second before the next day starts. Used by date-range
+    /// filters where the user picks "to: 2026-05-09" meaning "through the
+    /// rest of that day."
+    /// </summary>
+    public static DateTimeOffset EndOfMoscowDay(DateOnly date) =>
+        new DateTimeOffset(date.ToDateTime(TimeOnly.MinValue), Offset)
+            .AddDays(1).AddSeconds(-1);
+}

src/Marathon.Infrastructure/Scraping/Parsers/EventListingParserBase.cs

@@ -17,8 +17,6 @@ namespace Marathon.Infrastructure.Scraping.Parsers;
 /// </summary>
 public abstract class EventListingParserBase
 {
-    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
-
     protected readonly IServerTimeProvider ServerTimeProvider;
     protected readonly ILogger Logger;
 
@@ -36,7 +34,7 @@ public abstract class EventListingParserBase
         CancellationToken ct)
     {
         var serverTime = ServerTimeProvider.ExtractServerTime(html)
-            ?? DateTimeOffset.UtcNow.ToOffset(MoscowOffset);
+            ?? MoscowTime.Now;
 
         var config = AngleSharpConfig.Default;
         using var context = BrowsingContext.New(config);

src/Marathon.Infrastructure/Scraping/Parsers/EventOddsParser.cs

@@ -18,8 +18,6 @@ namespace Marathon.Infrastructure.Scraping.Parsers;
 /// </summary>
 public sealed partial class EventOddsParser : IEventOddsParser
 {
-    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
-
     private readonly IServerTimeProvider _serverTime;
     private readonly PeriodScopeMapper _periodMapper;
     private readonly ILogger<EventOddsParser> _logger;
@@ -69,7 +67,7 @@ public sealed partial class EventOddsParser : IEventOddsParser
         ArgumentNullException.ThrowIfNull(html);
 
         var capturedAt = _serverTime.ExtractServerTime(html)
-            ?? DateTimeOffset.UtcNow.ToOffset(MoscowOffset);
+            ?? MoscowTime.Now;
 
         var config = AngleSharpConfig.Default;
         using var context = BrowsingContext.New(config);

src/Marathon.Infrastructure/Scraping/Parsers/MoscowDateParser.cs

@@ -1,5 +1,6 @@
 using System.Globalization;
 using System.Text.RegularExpressions;
+using Marathon.Domain.ValueObjects;
 
 namespace Marathon.Infrastructure.Scraping.Parsers;
 
@@ -13,8 +14,6 @@ namespace Marathon.Infrastructure.Scraping.Parsers;
 /// </summary>
 public static partial class MoscowDateParser
 {
-    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
-
     // Matches "HH:MM"
     [GeneratedRegex(@"^\s*(\d{1,2}):(\d{2})\s*$", RegexOptions.CultureInvariant)]
     private static partial Regex TimeOnlyRegex();
@@ -70,7 +69,7 @@ public static partial class MoscowDateParser
             var scheduled = new DateTimeOffset(
                 today.Year, today.Month, today.Day,
                 hour, minute, 0,
-                MoscowOffset);
+                MoscowTime.Offset);
 
             // If the computed time is already in the past (same day but earlier),
             // that's fine — the event may have already started (live) or the listing
@@ -98,7 +97,7 @@ public static partial class MoscowDateParser
             if (candidate < DateOnly.FromDateTime(anchorDate))
                 year++; // e.g., anchor is Dec 2026 and event is in Jan 2027
 
-            return new DateTimeOffset(year, month, day, hour, minute, 0, MoscowOffset);
+            return new DateTimeOffset(year, month, day, hour, minute, 0, MoscowTime.Offset);
         }
 
         return null;

src/Marathon.Infrastructure/Scraping/Parsers/ResultsParser.cs

@@ -21,8 +21,6 @@ namespace Marathon.Infrastructure.Scraping.Parsers;
 /// </remarks>
 public sealed partial class ResultsParser : IResultsParser
 {
-    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
-
     private readonly ILogger<ResultsParser> _logger;
 
     // Matches score patterns like "2:1", "2:1 (1:1)", "2:1 (0:0) (2:1)"
@@ -101,7 +99,7 @@ public sealed partial class ResultsParser : IResultsParser
         if (string.IsNullOrWhiteSpace(eventIdRaw))
             return null;
 
-        var completedAt = DateTimeOffset.UtcNow.ToOffset(MoscowOffset);
+        var completedAt = MoscowTime.Now;
 
         return new EventResult(
             new DomainEventId(eventIdRaw),

src/Marathon.Infrastructure/Scraping/Parsers/ServerTimeProvider.cs

@@ -1,4 +1,5 @@
 using System.Text.RegularExpressions;
+using Marathon.Domain.ValueObjects;
 using Microsoft.Extensions.Logging;
 
 namespace Marathon.Infrastructure.Scraping.Parsers;
@@ -17,8 +18,6 @@ public sealed partial class ServerTimeProvider : IServerTimeProvider
         RegexOptions.CultureInvariant)]
     private static partial Regex ServerTimeRegex();
 
-    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
-
     private readonly ILogger<ServerTimeProvider> _logger;
 
     public ServerTimeProvider(ILogger<ServerTimeProvider> logger)
@@ -47,6 +46,6 @@ public sealed partial class ServerTimeProvider : IServerTimeProvider
         var minute = int.Parse(match.Groups[5].Value);
         var second = int.Parse(match.Groups[6].Value);
 
-        return new DateTimeOffset(year, month, day, hour, minute, second, MoscowOffset);
+        return new DateTimeOffset(year, month, day, hour, minute, second, MoscowTime.Offset);
     }
 }

src/Marathon.UI/Components/AnomalyCard.razor

@@ -215,14 +215,7 @@
         _                          => kind.ToString(),
     };
 
-    private string SportLabel(int code) => code switch
-    {
-        6      => L["Sport.Basketball"],
-        11     => L["Sport.Football"],
-        22723  => L["Sport.Tennis"],
-        43658  => L["Sport.Hockey"],
-        _      => string.Format(System.Globalization.CultureInfo.InvariantCulture, "Sport {0}", code),
-    };
+    private string SportLabel(int code) => SportLabels.Resolve(L, code);
 
     private static string FormatRate(decimal? r) => r is { } v
         ? v.ToString("0.00", System.Globalization.CultureInfo.InvariantCulture)

src/Marathon.UI/Components/ExportDialog.razor

@@ -113,7 +113,7 @@
 
     protected override void OnInitialized()
     {
-        var moscow = DateTimeOffset.UtcNow.ToOffset(TimeSpan.FromHours(3));
+        var moscow = MoscowTime.Now;
         _from = InitialFrom ?? moscow.AddDays(-1).Date;
         _to = InitialTo ?? moscow.AddDays(1).Date;
         _kind = InitialKind;
@@ -140,10 +140,9 @@
         try
         {
             // Use Moscow offset to match domain ScheduledAt invariant.
-            var moscow = TimeSpan.FromHours(3);
             var range = new AppDateRange(
-                new DateTimeOffset(_from.Value.Date, moscow),
-                new DateTimeOffset(_to.Value.Date.AddDays(1).AddSeconds(-1), moscow));
+                new DateTimeOffset(_from.Value.Date, MoscowTime.Offset),
+                MoscowTime.EndOfMoscowDay(DateOnly.FromDateTime(_to.Value.Date)));
 
             var path = await ExportUseCase.ExecuteAsync(range, _kind, CancellationToken.None);
             Dialog.Close(DialogResult.Ok(path));

src/Marathon.UI/Pages/Anomalies/AnomalyFeed.razor

@@ -252,8 +252,7 @@
     {
         if (DateTimeOffset.TryParse(e.Value?.ToString(), out var v))
         {
-            var moscow = TimeSpan.FromHours(3);
-            await UpdateFilter(_filter with { From = new DateTimeOffset(v.Date, moscow) });
+            await UpdateFilter(_filter with { From = new DateTimeOffset(v.Date, MoscowTime.Offset) });
         }
     }
 
@@ -261,8 +260,7 @@
     {
         if (DateTimeOffset.TryParse(e.Value?.ToString(), out var v))
         {
-            var moscow = TimeSpan.FromHours(3);
-            await UpdateFilter(_filter with { To = new DateTimeOffset(v.Date, moscow).AddDays(1).AddSeconds(-1) });
+            await UpdateFilter(_filter with { To = MoscowTime.EndOfMoscowDay(DateOnly.FromDateTime(v.Date)) });
         }
     }
 
@@ -283,14 +281,7 @@
         _                      => L["Anomaly.Severity.Low"],
     };
 
-    private string SportLabel(int code) => code switch
-    {
-        6      => L["Sport.Basketball"],
-        11     => L["Sport.Football"],
-        22723  => L["Sport.Tennis"],
-        43658  => L["Sport.Hockey"],
-        _      => string.Format(System.Globalization.CultureInfo.InvariantCulture, "Sport {0}", code),
-    };
+    private string SportLabel(int code) => SportLabels.Resolve(L, code);
 
     private static string FormatDate(DateTimeOffset? value)
         => value?.ToString("yyyy-MM-dd") ?? string.Empty;

src/Marathon.UI/Pages/Events/Detail.razor

@@ -306,14 +306,7 @@
         _ => "—",
     };
 
-    private string SportLabel(int code) => code switch
-    {
-        6      => L["Sport.Basketball"],
-        11     => L["Sport.Football"],
-        22723  => L["Sport.Tennis"],
-        43658  => L["Sport.Hockey"],
-        _      => $"Sport {code}",
-    };
+    private string SportLabel(int code) => SportLabels.Resolve(L, code);
 
     private string BetTypeLabel(BetType t) => t switch
     {

src/Marathon.UI/Pages/Results/ResultsList.razor

@@ -164,8 +164,6 @@
 </style>
 
 @code {
-    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
-
     private DateTimeOffset _from;
     private DateTimeOffset _to;
     private string _searchInput = string.Empty;
@@ -181,7 +179,7 @@
 
     protected override async Task OnInitializedAsync()
     {
-        var todayMoscow = new DateTimeOffset(DateTime.UtcNow.Date, TimeSpan.Zero).ToOffset(MoscowOffset);
+        var todayMoscow = new DateTimeOffset(DateTime.UtcNow.Date, TimeSpan.Zero).ToOffset(MoscowTime.Offset);
         _from = todayMoscow.AddDays(-30);
         _to   = todayMoscow.AddDays(1).AddSeconds(-1);
 
@@ -246,7 +244,7 @@
     {
         if (DateTimeOffset.TryParse(e.Value?.ToString(), out var v))
         {
-            _from = new DateTimeOffset(v.Date, MoscowOffset);
+            _from = new DateTimeOffset(v.Date, MoscowTime.Offset);
             await LoadAsync();
         }
     }
@@ -255,7 +253,7 @@
     {
         if (DateTimeOffset.TryParse(e.Value?.ToString(), out var v))
         {
-            _to = new DateTimeOffset(v.Date, MoscowOffset).AddDays(1).AddSeconds(-1);
+            _to = new DateTimeOffset(v.Date, MoscowTime.Offset).AddDays(1).AddSeconds(-1);
             await LoadAsync();
         }
     }
@@ -311,14 +309,7 @@
         _ => "draw",
     };
 
-    private string SportLabel(int code) => code switch
-    {
-        6      => L["Sport.Basketball"],
-        11     => L["Sport.Football"],
-        22723  => L["Sport.Tennis"],
-        43658  => L["Sport.Hockey"],
-        _      => $"Sport {code}",
-    };
+    private string SportLabel(int code) => SportLabels.Resolve(L, code);
 
     public void Dispose()
     {

src/Marathon.UI/Pages/Results/ResultsLoader.razor

@@ -204,8 +204,6 @@
 </style>
 
 @code {
-    private static readonly TimeSpan MoscowOffset = TimeSpan.FromHours(3);
-
     private DateTimeOffset _from;
     private DateTimeOffset _to;
     private LoaderMode _mode = LoaderMode.AllInRange;
@@ -234,7 +232,7 @@
 
     protected override async Task OnInitializedAsync()
     {
-        var todayMoscow = new DateTimeOffset(DateTime.UtcNow.Date, TimeSpan.Zero).ToOffset(MoscowOffset);
+        var todayMoscow = new DateTimeOffset(DateTime.UtcNow.Date, TimeSpan.Zero).ToOffset(MoscowTime.Offset);
         _from = todayMoscow.AddDays(-7);
         _to   = todayMoscow.AddDays(1).AddSeconds(-1);
         await ReloadCandidatesAsync();
@@ -347,7 +345,7 @@
     {
         if (DateTimeOffset.TryParse(e.Value?.ToString(), out var v))
         {
-            _from = new DateTimeOffset(v.Date, MoscowOffset);
+            _from = new DateTimeOffset(v.Date, MoscowTime.Offset);
             await ReloadCandidatesAsync();
         }
     }
@@ -356,7 +354,7 @@
     {
         if (DateTimeOffset.TryParse(e.Value?.ToString(), out var v))
         {
-            _to = new DateTimeOffset(v.Date, MoscowOffset).AddDays(1).AddSeconds(-1);
+            _to = new DateTimeOffset(v.Date, MoscowTime.Offset).AddDays(1).AddSeconds(-1);
             await ReloadCandidatesAsync();
         }
     }
@@ -400,14 +398,7 @@
         _ => o.ToString(),
     };
 
-    private string SportLabel(int code) => code switch
-    {
-        6      => L["Sport.Basketball"],
-        11     => L["Sport.Football"],
-        22723  => L["Sport.Tennis"],
-        43658  => L["Sport.Hockey"],
-        _      => $"Sport {code}",
-    };
+    private string SportLabel(int code) => SportLabels.Resolve(L, code);
 
     private static string FormatDate(DateTimeOffset value) => value.ToString("yyyy-MM-dd");
 

src/Marathon.UI/Pages/Shared/EventListShell.razor

@@ -437,8 +437,7 @@
     {
         if (DateTimeOffset.TryParse(e.Value?.ToString(), out var v))
         {
-            var moscow = TimeSpan.FromHours(3);
-            await UpdateFilter(_filter with { From = new DateTimeOffset(v.Date, moscow) });
+            await UpdateFilter(_filter with { From = new DateTimeOffset(v.Date, MoscowTime.Offset) });
         }
     }
 
@@ -446,8 +445,7 @@
     {
         if (DateTimeOffset.TryParse(e.Value?.ToString(), out var v))
         {
-            var moscow = TimeSpan.FromHours(3);
-            await UpdateFilter(_filter with { To = new DateTimeOffset(v.Date, moscow).AddDays(1).AddSeconds(-1) });
+            await UpdateFilter(_filter with { To = MoscowTime.EndOfMoscowDay(DateOnly.FromDateTime(v.Date)) });
         }
     }
 
@@ -519,14 +517,7 @@
     private static string FormatDate(DateTimeOffset value)
         => value.ToString("yyyy-MM-dd");
 
-    private string SportLabel(int code) => code switch
-    {
-        6      => L["Sport.Basketball"],
-        11     => L["Sport.Football"],
-        22723  => L["Sport.Tennis"],
-        43658  => L["Sport.Hockey"],
-        _      => $"Sport {code}",
-    };
+    private string SportLabel(int code) => SportLabels.Resolve(L, code);
 
     private readonly record struct RatesSnap(decimal? Win1, decimal? Draw, decimal? Win2);
 

src/Marathon.UI/Services/EventBrowsingState.cs

@@ -1,3 +1,5 @@
+using Marathon.Domain.ValueObjects;
+
 namespace Marathon.UI.Services;
 
 /// <summary>
@@ -54,8 +56,7 @@ public sealed class EventBrowsingState
         public static PageFilter Default(DateTime nowUtc)
         {
             // Default window: -1d .. +7d in Moscow time, the same TZ events use.
-            var moscow = TimeSpan.FromHours(3);
-            var midnight = new DateTimeOffset(nowUtc.Date, TimeSpan.Zero).ToOffset(moscow);
+            var midnight = new DateTimeOffset(nowUtc.Date, TimeSpan.Zero).ToOffset(MoscowTime.Offset);
             return new PageFilter(
                 From: midnight.AddDays(-1),
                 To: midnight.AddDays(7),

src/Marathon.UI/Services/SportLabels.cs

@@ -0,0 +1,26 @@
+using System.Globalization;
+using Marathon.UI.Resources;
+using Microsoft.Extensions.Localization;
+
+namespace Marathon.UI.Services;
+
+/// <summary>
+/// Single source of truth for the sport-code → display-label mapping that
+/// every list/detail page in the RCL needs. Resolves the four canonical
+/// data-sport-treeId values from the marathonbet.by spike (6 = basketball,
+/// 11 = football, 22723 = tennis, 43658 = hockey) against shared
+/// localization resources, with a stable invariant fallback for unknown
+/// codes so the UI degrades gracefully if the bookmaker adds a new sport.
+/// </summary>
+public static class SportLabels
+{
+    public static string Resolve(IStringLocalizer<SharedResource> localizer, int code) =>
+        code switch
+        {
+            6     => localizer["Sport.Basketball"],
+            11    => localizer["Sport.Football"],
+            22723 => localizer["Sport.Tennis"],
+            43658 => localizer["Sport.Hockey"],
+            _     => string.Format(CultureInfo.InvariantCulture, "Sport {0}", code),
+        };
+}