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.

tests/Marathon.UI.Tests/Pages/Events/DetailTests.cs

@@ -0,0 +1,71 @@
+using Bunit;
+using Marathon.UI.Pages.Events;
+using Marathon.UI.Services;
+using Marathon.UI.Tests.Support;
+
+namespace Marathon.UI.Tests.Pages.Events;
+
+public sealed class DetailTests : MarathonTestContext
+{
+    [Fact]
+    public void Renders_not_found_when_detail_is_null()
+    {
+        Browsing.Detail = null;
+        var cut = RenderComponent<Detail>(p => p.Add(d => d.EventCode, "missing"));
+        cut.WaitForAssertion(() =>
+        {
+            cut.Markup.Should().Contain("Detail.NotFound");
+        });
+    }
+
+    [Fact]
+    public void Renders_event_header_and_tabs_for_each_scope()
+    {
+        Browsing.Detail = TestData.Detail(id: "ABC-1");
+
+        var cut = RenderComponent<Detail>(p => p.Add(d => d.EventCode, "ABC-1"));
+
+        cut.WaitForAssertion(() =>
+        {
+            // Two tabs from the seeded detail (Match + Period 1).
+            cut.FindAll(".m-detail-tab").Count.Should().Be(2);
+            cut.Markup.Should().Contain("Arsenal");
+            cut.Markup.Should().Contain("Chelsea");
+            cut.Markup.Should().Contain("Detail.Tabs.Match");
+        });
+    }
+
+    [Fact]
+    public void Renders_snapshot_history_entries()
+    {
+        Browsing.Detail = TestData.Detail(
+            id: "ABC-2",
+            new OddsTimelinePoint(DateTimeOffset.UtcNow.AddMinutes(-30), 1.90m, 3.30m, 4.10m),
+            new OddsTimelinePoint(DateTimeOffset.UtcNow.AddMinutes(-15), 1.85m, 3.40m, 4.20m),
+            new OddsTimelinePoint(DateTimeOffset.UtcNow, 1.80m, 3.50m, 4.30m));
+
+        var cut = RenderComponent<Detail>(p => p.Add(d => d.EventCode, "ABC-2"));
+
+        cut.WaitForAssertion(() =>
+        {
+            // Three rows in history table (one per timeline point).
+            // We match the formatted rate cell text instead of generic table rows.
+            cut.Markup.Should().Contain("1.85");
+            cut.Markup.Should().Contain("1.80");
+            cut.Markup.Should().Contain("1.90");
+        });
+    }
+
+    [Fact]
+    public void Renders_chart_or_data_table_fallback()
+    {
+        Browsing.Detail = TestData.Detail(id: "ABC-3");
+        var cut = RenderComponent<Detail>(p => p.Add(d => d.EventCode, "ABC-3"));
+        cut.WaitForAssertion(() =>
+        {
+            cut.Markup.Should().Contain("Detail.Chart.Title");
+            // <details> fallback for screen readers
+            cut.Markup.Should().Contain("Detail.Chart.AccessibleSummary");
+        });
+    }
+}