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/config.go

@@ -1,6 +1,7 @@
 package ai_summarizer
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"time"
@@ -15,6 +16,10 @@ type Config struct {
 	APIRetryCount int           // Number of retry attempts for failed API requests
 	APIRetryDelay time.Duration // Delay between retry attempts
 
+	// OnSuccessfulTranslation is called after a successful POST /ai/translate request.
+	// source identifies the caller (daily_job or manual_trigger).
+	OnSuccessfulTranslation func(ctx context.Context, source string) error
+
 	// MinIO storage settings
 	MinioEndpoint  string        // MinIO endpoint, e.g. "ai-host:9000"
 	MinioAccessKey string        // MinIO access key ID