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/OddsCell.razor

@@ -0,0 +1,104 @@
+@*
+    OddsCell — tabular mono rendering of a decimal odds rate, with an inline
+    direction marker (▲ amber rising, ▼ red falling, em-dash unchanged) when
+    the value differs from a previous render. Drives the visual indicator
+    that Phase 6 promises for live-list odds movement.
+
+    Rate is the current value. Previous (optional) is the prior value the
+    caller wants compared against. Caller decides what "previous" means
+    (last refresh / last snapshot) and tracks it in its own state.
+*@
+
+@{
+    var direction = Direction;
+    var directionGlyph = direction switch
+    {
+        Trend.Up   => "▲", // ▲
+        Trend.Down => "▼", // ▼
+        _          => "—", // em-dash
+    };
+    var directionClass = direction switch
+    {
+        Trend.Up   => "is-up",
+        Trend.Down => "is-down",
+        _          => "is-flat",
+    };
+    var ariaTrend = direction switch
+    {
+        Trend.Up   => "rising",
+        Trend.Down => "falling",
+        _          => "unchanged",
+    };
+}
+
+<span class="m-odds @directionClass" aria-label="@AriaPrefix @Formatted (@ariaTrend)" data-trend="@ariaTrend">
+    <span class="m-odds__value m-mono" data-numeric>@Formatted</span>
+    @if (ShowTrend)
+    {
+        <span class="m-odds__delta" aria-hidden="true">@directionGlyph</span>
+    }
+</span>
+
+<style>
+    .m-odds {
+        display: inline-flex;
+        align-items: baseline;
+        gap: 6px;
+        min-width: 56px;
+        white-space: nowrap;
+    }
+    .m-odds__value {
+        font-feature-settings: "tnum" 1, "lnum" 1;
+        font-weight: 500;
+        color: var(--m-c-ink);
+        font-size: 0.9375rem;
+    }
+    .m-odds__delta {
+        font-family: var(--m-font-mono);
+        font-size: 0.6875rem;
+        line-height: 1;
+        color: var(--m-c-ink-soft);
+        transition: color 220ms ease;
+    }
+    .m-odds.is-up .m-odds__delta { color: var(--m-c-accent); }
+    .m-odds.is-down .m-odds__delta { color: var(--m-c-anomaly); }
+    .m-odds.is-flat .m-odds__delta { color: var(--m-c-ink-soft); }
+
+    .m-odds.is-up .m-odds__value,
+    .m-odds.is-down .m-odds__value {
+        animation: m-odds-flash 1200ms ease-out 1;
+    }
+
+    @@keyframes m-odds-flash {
+        0%   { background: color-mix(in srgb, currentColor 14%, transparent); }
+        100% { background: transparent; }
+    }
+
+    @@media (prefers-reduced-motion: reduce) {
+        .m-odds.is-up .m-odds__value,
+        .m-odds.is-down .m-odds__value { animation: none; }
+    }
+</style>
+
+@code {
+    [Parameter] public decimal? Rate { get; set; }
+    [Parameter] public decimal? Previous { get; set; }
+    [Parameter] public bool ShowTrend { get; set; } = true;
+    [Parameter] public string AriaPrefix { get; set; } = "Odds";
+    [Parameter] public string EmptyPlaceholder { get; set; } = "—";
+
+    private string Formatted => Rate is { } r ? r.ToString("0.00") : EmptyPlaceholder;
+
+    private Trend Direction
+    {
+        get
+        {
+            if (Rate is not { } r || Previous is not { } p) return Trend.Flat;
+            if (r > p) return Trend.Up;
+            if (r < p) return Trend.Down;
+            return Trend.Flat;
+        }
+    }
+
+    private enum Trend { Flat, Up, Down }
+}