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/SportIcon.razor

@@ -0,0 +1,78 @@
+@*
+    SportIcon — minimal, distinctive inline-SVG icons per sport. Inline (not
+    icon library) so the wordmark stays editorial-quant: thin strokes, sharp
+    corners, no shadowing. Coverage matches Phase 0 spike findings:
+    Basketball=6, Football=11, Tennis=22723, Hockey=43658.
+*@
+
+<span class="m-sport @ClassName" role="img" aria-label="@Label" title="@Label" data-sport="@Code">
+    @SvgContent
+</span>
+
+<style>
+    .m-sport {
+        display: inline-flex;
+        align-items: center;
+        justify-content: center;
+        width: var(--m-sport-size, 18px);
+        height: var(--m-sport-size, 18px);
+        color: var(--m-sport-color, var(--m-c-ink-soft));
+        flex: 0 0 auto;
+    }
+    .m-sport svg { width: 100%; height: 100%; display: block; }
+    .m-sport[data-sport="6"] { color: #d97706; }
+    .m-sport[data-sport="11"] { color: #15803d; }
+    .m-sport[data-sport="22723"] { color: #0369a1; }
+    .m-sport[data-sport="43658"] { color: #6d28d9; }
+    [data-theme="dark"] .m-sport { filter: brightness(1.1); }
+</style>
+
+@code {
+    [Parameter, EditorRequired] public int Code { get; set; }
+    [Parameter] public string? Label { get; set; }
+    [Parameter] public string? ClassName { get; set; }
+
+    private MarkupString SvgContent => new(GetSvg(Code));
+
+    private static string GetSvg(int code) => code switch
+    {
+        6      => Basketball,
+        11     => Football,
+        22723  => Tennis,
+        43658  => Hockey,
+        _      => Generic,
+    };
+
+    // SVG glyphs — single-quote attributes so the entire literal can stay on one line.
+    private const string Basketball =
+        "<svg viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='1.6' stroke-linecap='round'>" +
+        "<circle cx='12' cy='12' r='9' />" +
+        "<path d='M3 12h18 M12 3v18 M5 5c4 4 10 4 14 0 M5 19c4-4 10-4 14 0' />" +
+        "</svg>";
+
+    private const string Football =
+        "<svg viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='1.6' stroke-linejoin='round'>" +
+        "<circle cx='12' cy='12' r='9' />" +
+        "<polygon points='12,7 16.5,10 14.5,15 9.5,15 7.5,10' />" +
+        "</svg>";
+
+    private const string Tennis =
+        "<svg viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='1.6' stroke-linecap='round'>" +
+        "<circle cx='12' cy='12' r='9' />" +
+        "<path d='M3.5 9 C 9 9 15 15 20.5 15' />" +
+        "<path d='M3.5 15 C 9 15 15 9 20.5 9' />" +
+        "</svg>";
+
+    private const string Hockey =
+        "<svg viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='1.6' stroke-linecap='round'>" +
+        "<ellipse cx='12' cy='14' rx='8' ry='3' />" +
+        "<path d='M4 14 L4 11 M20 14 L20 11' />" +
+        "<path d='M6 7 L18 4' />" +
+        "</svg>";
+
+    private const string Generic =
+        "<svg viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='1.6'>" +
+        "<circle cx='12' cy='12' r='9' />" +
+        "<circle cx='12' cy='12' r='3' />" +
+        "</svg>";
+}