feat(phase-6): event browsing UI — pre-match/live lists, detail page, +26 bUnit tests

Replaces PreMatch/Live placeholder pages with a shared EventListShell
(filter chips, date range, sortable virtualized-friendly table, debounced
search, live auto-refresh with odds-movement indicators) and adds a new
/events/{eventCode} detail page (asymmetric header lockup, dynamic
Match/Period tabs, Plotly.Blazor odds-over-time chart with accessible
data-table fallback, snapshot history, Excel export modal).

New primitives matching Phase 5's editorial-quant system:
- SportIcon: inline SVGs per sport (basketball=6, football=11,
  tennis=22723, hockey=43658, generic fallback)
- OddsCell: tabular mono with ▲/▼/— delta + flash on change
  (prefers-reduced-motion honored)
- OddsTimeline: Plotly.Blazor wrapper with theme-aware colors and
  <details>/<summary> data-table screen-reader fallback
- ExportDialog: From/To pickers + ExportKind radio + Esc/Enter
  keyboard, surfaces use-case errors inline
- EventListShell: shared section shell for PreMatch/Live cadence

State + service split keeps the RCL host-agnostic:
- IEventBrowsingService / EventBrowsingService — wraps repos, returns
  view-model records (EventListItem, EventDetail, EventScopeBoard,
  BetRow, OddsTimelinePoint, SnapshotHistoryEntry); pages never see
  EF or domain entities directly.
- EventBrowsingState — singleton (per-circuit in BlazorWebView) holding
  immutable PageFilter records for PreMatch and Live.

Plotly.Blazor 5.4.1 added (latest .NET 8 line; 7.x has breaking changes).
+59 RU/EN localization keys following the Phase 5 dot-segmented convention.

Tests: +26 bUnit tests (PreMatch/Live/Detail pages, OddsCell/SportIcon/
ExportDialog components, EventBrowsingState). Total 228/228 passing
(Domain 96 + Application 15 + Infrastructure 80 + UI 37; baseline 202).
Build clean (0/0).

PLAN.md: P2/P3/P5 top-level checkboxes ticked; P6 row marked Done.

src/Marathon.UI/Components/ExportDialog.razor

@@ -0,0 +1,174 @@
+@*
+    ExportDialog — modal that collects a DateRange + ExportKind, then calls
+    ExportToExcelUseCase. Reports back via DialogResult so the caller can
+    show a snackbar with the file path. Keyboard: Esc to cancel, Enter to
+    submit.
+*@
+
+@using Marathon.Application.UseCases
+@using AppDateRange = Marathon.Application.Storage.DateRange
+@using ExportKind = Marathon.Application.Storage.ExportKind
+@inject IStringLocalizer<SharedResource> L
+@inject ExportToExcelUseCase ExportUseCase
+@inject ILogger<ExportDialog> Logger
+
+<MudDialog @key="@(_kind.ToString())" Class="m-export-dialog">
+    <TitleContent>
+        <span class="m-kicker">@L["Export.Kicker"]</span>
+        <h2 style="font-family: var(--m-font-display); font-weight: 400; font-size: 1.5rem; margin: var(--m-space-2) 0 0;">
+            @L["Export.Title"]
+        </h2>
+    </TitleContent>
+    <DialogContent>
+        <div style="display: grid; gap: var(--m-space-4); padding: var(--m-space-2) 0;" @onkeydown="HandleKeyDown">
+            <div class="m-field-row">
+                <div>
+                    <label style="font-weight: 500;">@L["Export.DateRange.From"]</label>
+                </div>
+                <div>
+                    <MudDatePicker
+                        @bind-Date="_from"
+                        Label="@L["Export.DateRange.From"]"
+                        DateFormat="yyyy-MM-dd"
+                        Variant="Variant.Outlined" />
+                </div>
+            </div>
+
+            <div class="m-field-row">
+                <div>
+                    <label style="font-weight: 500;">@L["Export.DateRange.To"]</label>
+                </div>
+                <div>
+                    <MudDatePicker
+                        @bind-Date="_to"
+                        Label="@L["Export.DateRange.To"]"
+                        DateFormat="yyyy-MM-dd"
+                        Variant="Variant.Outlined" />
+                </div>
+            </div>
+
+            <div class="m-field-row">
+                <div>
+                    <label style="font-weight: 500;">@L["Export.Kind.Label"]</label>
+                </div>
+                <div>
+                    <MudRadioGroup T="ExportKind" @bind-Value="_kind">
+                        <MudRadio Value="@(ExportKind.PreMatch)" Color="Color.Primary">@L["Export.Kind.PreMatch"]</MudRadio>
+                        <MudRadio Value="@(ExportKind.Live)" Color="Color.Primary">@L["Export.Kind.Live"]</MudRadio>
+                        <MudRadio Value="@(ExportKind.Combined)" Color="Color.Primary">@L["Export.Kind.Combined"]</MudRadio>
+                    </MudRadioGroup>
+                </div>
+            </div>
+
+            @if (_error is not null)
+            {
+                <div role="alert" class="m-export-dialog__error">
+                    @_error
+                </div>
+            }
+        </div>
+    </DialogContent>
+    <DialogActions>
+        <MudButton OnClick="Cancel" Variant="Variant.Text">@L["Export.Cancel"]</MudButton>
+        <MudButton OnClick="Submit"
+                   Color="Color.Primary"
+                   Variant="Variant.Filled"
+                   Disabled="@_busy">
+            @if (_busy)
+            {
+                <MudProgressCircular Indeterminate="true" Size="Size.Small" Color="Color.Inherit" />
+                <span style="margin-left: 8px;">@L["Common.Loading"]</span>
+            }
+            else
+            {
+                @L["Export.Submit"]
+            }
+        </MudButton>
+    </DialogActions>
+</MudDialog>
+
+<style>
+    .m-export-dialog__error {
+        background: rgba(220, 38, 38, 0.08);
+        border-left: 3px solid var(--m-c-anomaly);
+        padding: var(--m-space-3);
+        font-family: var(--m-font-mono);
+        font-size: 0.8125rem;
+        color: var(--m-c-anomaly);
+    }
+</style>
+
+@code {
+    [CascadingParameter] private MudDialogInstance Dialog { get; set; } = default!;
+
+    [Parameter] public DateTime? InitialFrom { get; set; }
+    [Parameter] public DateTime? InitialTo { get; set; }
+    [Parameter] public ExportKind InitialKind { get; set; } = ExportKind.Combined;
+
+    private DateTime? _from;
+    private DateTime? _to;
+    private ExportKind _kind;
+    private bool _busy;
+    private string? _error;
+
+    protected override void OnInitialized()
+    {
+        var moscow = DateTimeOffset.UtcNow.ToOffset(TimeSpan.FromHours(3));
+        _from = InitialFrom ?? moscow.AddDays(-1).Date;
+        _to = InitialTo ?? moscow.AddDays(1).Date;
+        _kind = InitialKind;
+    }
+
+    private void Cancel() => Dialog.Cancel();
+
+    private async Task Submit()
+    {
+        if (_from is null || _to is null)
+        {
+            _error = L["Export.Error.MissingDates"];
+            return;
+        }
+        if (_from > _to)
+        {
+            _error = L["Export.Error.InvalidRange"];
+            return;
+        }
+
+        _error = null;
+        _busy = true;
+        StateHasChanged();
+        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));
+
+            var path = await ExportUseCase.ExecuteAsync(range, _kind, CancellationToken.None);
+            Dialog.Close(DialogResult.Ok(path));
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError(ex, "Export failed");
+            _error = L["Export.Error.Failed"].Value + " — " + ex.Message;
+        }
+        finally
+        {
+            _busy = false;
+            StateHasChanged();
+        }
+    }
+
+    private async Task HandleKeyDown(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs e)
+    {
+        if (e.Key == "Enter" && !_busy)
+        {
+            await Submit();
+        }
+        else if (e.Key == "Escape")
+        {
+            Cancel();
+        }
+    }
+}