chore(analytics): remove dead day-hour heatmap (Unit 5) (#45)

src/InboxIntel.Infrastructure/Analytics/AnalyticsService.cs

@@ -16,11 +16,10 @@ public class AnalyticsService : IAnalyticsService
         var health = await GetInboxHealthAsync(userId, ct);
         var top = await GetTopSendersAsync(userId, 10, ct);
         var volume = await GetVolumeOverTimeAsync(userId, 90, ct);
-        var heatmap = await GetHeatmapAsync(userId, ct);
         var attachments = await GetAttachmentBreakdownAsync(userId, ct);
 
         return new DashboardSummaryDto(
-            health, health.TotalEmails, health.UnreadEmails, top, volume, heatmap, attachments,
+            health, health.TotalEmails, health.UnreadEmails, top, volume, attachments,
             health.EstimatedStorageBytes);
     }
 
@@ -75,19 +74,6 @@ public class AnalyticsService : IAnalyticsService
             .ToList();
     }
 
-    public async Task<IReadOnlyList<HeatmapCellDto>> GetHeatmapAsync(Guid userId, CancellationToken ct = default)
-    {
-        var raw = await _db.Emails
-            .Where(e => e.UserId == userId)
-            .Select(e => new { e.SentAtUtc })
-            .ToListAsync(ct);
-
-        return raw
-            .GroupBy(x => new { Dow = (int)x.SentAtUtc.DayOfWeek, Hour = x.SentAtUtc.Hour })
-            .Select(g => new HeatmapCellDto(g.Key.Dow, g.Key.Hour, g.Count()))
-            .ToList();
-    }
-
     public async Task<IReadOnlyList<CategoryHeatmapCellDto>> GetCategoryHeatmapAsync(Guid userId, CancellationToken ct = default)
     {
         var raw = await _db.Emails