Enhance dashboard summary and statistics with new fields and caching improvements

- Added new field `Days` and `ScrapedTED` to `SummaryResponse` for tracking daily TED scrape counts.
- Updated `SummaryQuery` to include `Days` parameter for querying scraped TED data.
- Modified `Summary` handler to accept and process the new `Days` parameter.
- Refactored `Summary` method in the repository to support the new `Days` parameter and improved aggregation logic.
- Enhanced caching logic in the service layer to utilize a composite cache key based on `closingWindowSec` and `days`, improving cache management and retrieval efficiency.

This update improves the dashboard's functionality by providing more detailed insights into TED scraping activities and optimizing the caching strategy for better performance.

internal/dashboard/entity.go

@@ -2,15 +2,17 @@ package dashboard
 
 // SummaryResponse powers hero pills and stat cards.
 type SummaryResponse struct {
-	TotalTenders        int64   `json:"total_tenders"`
-	ActiveTenders       int64   `json:"active_tenders"`
-	AwardedTenders      int64   `json:"awarded_tenders"`
-	ExpiredTenders      int64   `json:"expired_tenders"`
-	CancelledTenders    int64   `json:"cancelled_tenders"`
-	ClosingSoon         int64   `json:"closing_soon"`
-	TotalEstimatedValue float64 `json:"total_estimated_value"`
-	ValueCurrency       string  `json:"value_currency"`
-	GeneratedAt         int64   `json:"generated_at"`
+	TotalTenders        int64        `json:"total_tenders"`
+	ActiveTenders       int64        `json:"active_tenders"`
+	AwardedTenders      int64        `json:"awarded_tenders"`
+	ExpiredTenders      int64        `json:"expired_tenders"`
+	CancelledTenders    int64        `json:"cancelled_tenders"`
+	ClosingSoon         int64        `json:"closing_soon"`
+	TotalEstimatedValue float64      `json:"total_estimated_value"`
+	ValueCurrency       string       `json:"value_currency"`
+	Days                int          `json:"days"`
+	ScrapedTED          []TrendPoint `json:"scraped_ted"`
+	GeneratedAt         int64        `json:"generated_at"`
 }
 
 // TrendResponse powers the tender flow chart.
@@ -96,8 +98,7 @@ type StatisticsReportResponse struct {
 
 // StatisticsDailySeries contains per-day chart series.
 type StatisticsDailySeries struct {
-	ScrapedTED       []TrendPoint `json:"scraped_ted"`
-	ScrapedDocuments []TrendPoint `json:"scraped_documents"`
+	ScrapedDocuments  []TrendPoint `json:"scraped_documents"`
 	TranslatedNotices []TrendPoint `json:"translated_notices"`
 }