feat: prioritize trader analytics via LastAnalyzedAt and add force-analyze endpoint

src/Predictalytics.Worker/Services/TraderAnalyticsWorker.cs

@@ -40,21 +40,23 @@ public class TraderAnalyticsWorker : BackgroundService
 
     private async Task RunAnalyticsAsync(CancellationToken ct)
     {
-        var cutoff30d = DateTime.UtcNow.AddDays(-30);
         List<int> traderIds;
         
         using (var scope = _services.CreateScope())
         {
             var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
-            // Find traders active in the last 30 days
-            traderIds = await db.Trades
-                .Where(t => t.ExecutedAt >= cutoff30d)
-                .Select(t => t.TraderId)
-                .Distinct()
+            // Find traders who have never been analyzed, or whose last analysis was before their latest trade.
+            // Prioritize never-analyzed traders.
+            traderIds = await db.Traders
+                .Where(t => t.LastAnalyzedAt == null || t.Trades.Any(tr => tr.ExecutedAt > t.LastAnalyzedAt))
+                .OrderBy(t => t.LastAnalyzedAt == null ? 0 : 1)
+                .ThenBy(t => t.LastAnalyzedAt)
+                .Select(t => t.Id)
+                .Take(500) // Limit batch size to prevent long-running loops without save
                 .ToListAsync(ct);
         }
 
-        _logger.LogInformation("Found {Count} active traders to analyze", traderIds.Count);
+        _logger.LogInformation("Found {Count} active or unanalyzed traders to update", traderIds.Count);
 
         foreach (var id in traderIds)
         {