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.

pkg/ai_summarizer/entities.go

@@ -109,8 +109,14 @@ type TranslateRequest struct {
 	Title               string `json:"title"`
 	Description         string `json:"description"`
 	Language            string `json:"language"`
+	RequestSource       string `json:"-"` // internal: daily_job | manual_trigger
 }
 
+const (
+	TranslationRequestSourceDailyJob      = "daily_job"
+	TranslationRequestSourceManualTrigger = "manual_trigger"
+)
+
 // TranslateResponse represents the translation payload from POST /ai/translate.
 type TranslateResponse struct {
 	ContractFolderID      string `json:"contract_folder_id"`