Refactor AI summarizer client initialization to include MongoDB manager and add statistics endpoint

- Updated `InitAISummarizerClient` to accept `mongoManager` for tracking translation success.
- Introduced new `Statistics` endpoint in the dashboard to fetch scraping and translation statistics.
- Enhanced `TranslationWorker` to utilize the new success counter for tracking successful translations.
- Added necessary data structures and query forms for statistics reporting.

This refactor improves the tracking of AI translation success and provides new insights through the dashboard statistics.

internal/dashboard/service.go

@@ -25,6 +25,7 @@ type Service interface {
 	NoticeTypes(ctx context.Context) (*NoticeTypesResponse, error)
 	ClosingSoon(ctx context.Context, query ClosingSoonQuery) (*ClosingSoonResponse, error)
 	Recent(ctx context.Context, query RecentQuery) (*RecentResponse, error)
+	Statistics(ctx context.Context, query StatisticsQuery) (*StatisticsReportResponse, error)
 }
 
 type service struct {
@@ -157,6 +158,25 @@ func (s *service) Recent(ctx context.Context, query RecentQuery) (*RecentRespons
 	}, nil
 }
 
+func (s *service) Statistics(ctx context.Context, query StatisticsQuery) (*StatisticsReportResponse, error) {
+	days := trendDays(query.Days)
+	startUnix := trendStartUnix(days)
+
+	s.logger.Info("Fetching dashboard statistics report", map[string]interface{}{
+		"days": days,
+	})
+
+	out, err := s.repo.Statistics(ctx, days, startUnix)
+	if err != nil {
+		s.logger.Error("Failed to fetch dashboard statistics report", map[string]interface{}{
+			"error": err.Error(),
+		})
+		return nil, fmt.Errorf("dashboard statistics: %w", err)
+	}
+
+	return out, nil
+}
+
 func closingWindowHours(hours int) int {
 	if hours <= 0 {
 		return defaultClosingWindowHours