feat(home): surface forward-test P&L on the dashboard

Adds a forward-test (paper-trading) net-P&L tile to the Home dashboard, shown only
once the worker has opened or settled any paper bet. Reuses the existing
IPaperTradingService aggregation (settled-only net + open count) so there is one
definition of the figure, and makes the H4 forward-test result visible from the
landing page instead of only its own route.

- DashboardSummary gains Paper{OpenCount,SettledCount,NetProfit,RoiPercent}
  (default-valued, so existing constructions are unaffected) + HasPaperTrades;
  DashboardSummaryService injects IPaperTradingService; Home tile + en/ru resx.

src/Marathon.UI/Pages/Home.razor

@@ -24,6 +24,10 @@
                   Delta="@AnomaliesDelta"
                   Anomaly="true" />
         <StatCard Label="@L["Home.Stat.Coverage"]" Value="@_summary.SportsCovered.ToString()" />
+        @if (_summary.HasPaperTrades)
+        {
+            <StatCard Label="@L["Home.Stat.ForwardPnl"]" Value="@PaperNet" Delta="@PaperDelta" />
+        }
     </div>
 
     <div class="m-grid--asym m-rise m-rise-3" style="margin-top: var(--m-space-6);">
@@ -114,6 +118,22 @@
         ? string.Format(CultureInfo.CurrentCulture, L["Home.Stat.NewToday"], _summary.AnomaliesToday)
         : null;
 
+    // Forward-test headline: settled-only net P&L, with open-bet count as the delta line.
+    private string PaperNet
+    {
+        get
+        {
+            if (_summary.PaperSettledCount == 0) return "—";
+            var v = _summary.PaperNetProfit;
+            var sign = v > 0m ? "+" : (v < 0m ? "-" : "");
+            return sign + Math.Abs(v).ToString("0.00", CultureInfo.InvariantCulture);
+        }
+    }
+
+    private string? PaperDelta => _summary.PaperOpenCount > 0
+        ? string.Format(CultureInfo.CurrentCulture, L["Home.Stat.ForwardOpen"], _summary.PaperOpenCount)
+        : null;
+
     protected override async Task OnInitializedAsync()
     {
         try