Improve result modal and Envato previews

backend/services/ranker.go

@@ -2,9 +2,11 @@ package services
 
 import (
 	"fmt"
+	"math/rand"
 	"sort"
 	"strings"
 	"sync"
+	"time"
 )
 
 const GeminiFallbackReason = "Gemini Vision 응답이 부족해 키워드 기준으로 보강된 결과입니다."
@@ -193,6 +195,21 @@ func BuildFallbackRecommendations(ranked []SearchResult, limit int, reason strin
 	return fallback
 }
 
+func RandomizeTopRecommendations(items []AIRecommendation, window int) []AIRecommendation {
+	if len(items) < 2 || window < 2 {
+		return items
+	}
+
+	limit := min(window, len(items))
+	shuffled := make([]AIRecommendation, len(items))
+	copy(shuffled, items)
+	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
+	rng.Shuffle(limit, func(i, j int) {
+		shuffled[i], shuffled[j] = shuffled[j], shuffled[i]
+	})
+	return shuffled
+}
+
 func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult, limit int) []AIRecommendation {
 	merged := make([]AIRecommendation, 0, min(limit, len(ranked)))
 	seen := map[string]bool{}