Fix embedded-server endpoint drift, add Recalculate All Traders button

- Shared ApiConfiguration.MapPredictalyticsEndpoints() used by both the
  standalone API and the embedded WinForms Kestrel server: the embedded
  host was missing /api/watchlist and /api/dev (empty watchlist page),
  the standalone host was missing /api/search.
- New Development menu action "Recalculate All Traders": backfills
  ResolutionOutcome from snapped outcome prices, wipes derived analytics
  (snapshots, category stats, rebuildable positions), zeroes aggregates
  and marks every trader for re-analysis. Raw trades untouched.
- Static files now served with Cache-Control: no-cache in both hosts,
  plus ?v= cache-buster on app.js/style.css (stale browser JS masked
  earlier UI fixes).
- Watchlist hardened: endpoint null-safe, real Analytics.CopytradingScore,
  Platform field; repository includes Trader.Analytics; page shows a
  visible error row instead of staying silently blank.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Predictalytics.WinFormsHost/MainForm.cs

@@ -233,6 +233,46 @@ public partial class MainForm : Form
         }
     }
 
+    private async void btn_recalcAll_Click(object? sender, EventArgs e)
+    {
+        if (_workerRunning)
+        {
+            MessageBox.Show("Recalculation cannot be started while background workers are running. Stop the server first.",
+                "Workers Busy", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+            return;
+        }
+
+        var confirm = MessageBox.Show(
+            "This deletes all DERIVED analytics data (positions, daily snapshots, category stats) " +
+            "and marks every trader for full recalculation.\n\n" +
+            "Raw trades and markets are NOT touched.\n\n" +
+            "After this, start the server: the analytics worker rebuilds every trader with the current " +
+            "engine (runs in the background, can take several hours for large trader counts).\n\nContinue?",
+            "Recalculate All Traders", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
+        if (confirm != DialogResult.Yes) return;
+
+        try
+        {
+            btn_recalcAll.Enabled = false;
+            Log.Information("Manual full recalculation reset triggered...");
+
+            using var cts = new CancellationTokenSource();
+            var summary = await _webServer!.RunRecalculateAllTradersAsync(cts.Token);
+
+            MessageBox.Show($"Reset complete:\n\n{summary}\n\nNow start the server to rebuild the analytics.",
+                "Recalculate All Traders", MessageBoxButtons.OK, MessageBoxIcon.Information);
+        }
+        catch (Exception ex)
+        {
+            Log.Error(ex, "Full recalculation reset failed");
+            MessageBox.Show($"Recalculation reset failed: {ex.Message}", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
+        }
+        finally
+        {
+            btn_recalcAll.Enabled = true;
+        }
+    }
+
     private async Task UpdateDbSizeAsync()
     {
         try