Add scrapedDocumentsScanner interface and enhance document scanning logic

- Introduced the `scrapedDocumentsScanner` interface to facilitate scanning of scraped documents from MinIO, returning both procedure summaries and daily document counts.
- Updated the `ListProceduresWithDocuments` method to utilize the new scanning functionality, improving data retrieval efficiency.
- Enhanced the `scrapedDocumentsPerDay` method to filter daily counts based on a specified start date, ensuring accurate reporting of document statistics.
- Added unit tests for the new scanning logic and daily counts filtering, ensuring robust functionality and error handling.

This update enhances the dashboard's document management capabilities, providing better insights into scraped documents and their daily counts.

internal/dashboard/repository.go

@@ -22,6 +22,11 @@ type ProcedureDocumentsLister interface {
 	ListProceduresWithDocuments(ctx context.Context) ([]ai_summarizer.ProcedureDocumentsSummary, error)
 }
 
+// scrapedDocumentsScanner optionally scans MinIO for per-day document counts in the same pass.
+type scrapedDocumentsScanner interface {
+	ScanScrapedDocuments(ctx context.Context) ([]ai_summarizer.ProcedureDocumentsSummary, map[string]int64, error)
+}
+
 const defaultValueCurrency = "EUR"
 
 // Repository defines dashboard data access.