refactor: migrate all log statements to structured logger calls for improved observability

internal/db/tasks.go

@@ -4,7 +4,8 @@ import (
 	"database/sql"
 	"encoding/json"
 	"fmt"
-	"log"
+
+	"github.com/hireme/hireme/internal/logger"
 )
 
 // QueueStats holds task queue counters
@@ -96,7 +97,7 @@ func (db *DB) FailTask(id int64, errStr string) error {
 	var retryCount int
 	err := db.QueryRow(`SELECT retry_count FROM tasks WHERE id = ?`, id).Scan(&retryCount)
 	if err != nil {
-		log.Printf("[DB] FailTask: failed to get retry_count for task %d: %v", id, err)
+		logger.Log.Errorw("FailTask: failed to get retry_count", "component", "DB", "task_id", id, "error", err)
 		return err
 	}