Improve modal fit and Gemini search refinement

backend/services/ranker.go

@@ -11,7 +11,7 @@ import (
 
 const GeminiFallbackReason = "Gemini Vision 응답이 부족해 키워드 기준으로 보강된 결과입니다."
 const FallbackPreviewReason = "Fallback due to missing provider preview."
-const PendingVisualReason = "Ranked candidate pending stronger visual evidence."
+const SupplementalFallbackReason = "추가 탐색 후에도 충분한 확신 후보가 부족해 시각 자산이 있는 후보를 제한적으로 보강했습니다."
 
 type GeminiBatchStats struct {
 	CandidateCap      int      `json:"candidateCap"`
@@ -258,6 +258,7 @@ func BuildFallbackRecommendations(ranked []SearchResult, limit int, reason strin
 			Source:          item.Source,
 			Reason:          reason,
 			Recommended:     false,
+			Assessment:      "unclear",
 		}))
 	}
 	return fallback
@@ -370,18 +371,22 @@ func NeedsSupplementalExploration(items []AIRecommendation) bool {
 
 	recommendedCount := 0
 	negativeCount := 0
+	unclearCount := 0
 	for _, item := range items {
-		if item.Recommended {
+		if item.Recommended && item.Assessment == "positive" {
 			recommendedCount++
 		}
-		if looksNegativeReason(item.Reason) {
+		if IsExcludedAssessment(item.Assessment) || looksNegativeReason(item.Reason) {
 			negativeCount++
 		}
+		if item.Assessment == "unclear" {
+			unclearCount++
+		}
 	}
-	if recommendedCount >= 3 {
+	if recommendedCount >= 4 {
 		return false
 	}
-	return negativeCount >= max(2, len(items)/2)
+	return negativeCount >= max(2, len(items)/3) || unclearCount >= max(2, len(items)/2)
 }
 
 func looksNegativeReason(reason string) bool {
@@ -403,11 +408,9 @@ func looksNegativeReason(reason string) bool {
 func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult, limit int) []AIRecommendation {
 	merged := make([]AIRecommendation, 0, min(limit, len(ranked)))
 	seen := map[string]bool{}
-	fillerCount := 0
-	maxFiller := min(4, limit)
 
 	for _, item := range recommended {
-		if !item.Recommended {
+		if !item.Recommended || item.Assessment != "positive" {
 			continue
 		}
 		if item.Link == "" || seen[item.Link] {
@@ -421,7 +424,10 @@ func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult,
 		if item.Recommended || item.Link == "" || seen[item.Link] || len(merged) >= limit {
 			continue
 		}
-		if looksNegativeReason(item.Reason) || strings.Contains(item.Reason, GeminiFallbackReason) {
+		if IsExcludedAssessment(item.Assessment) || looksNegativeReason(item.Reason) || strings.Contains(item.Reason, GeminiFallbackReason) {
+			continue
+		}
+		if item.Assessment == "unclear" {
 			continue
 		}
 		if strings.TrimSpace(item.PreviewVideoURL) == "" && !hasUsableThumbnail(item.ThumbnailURL) {
@@ -430,32 +436,6 @@ func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult,
 		seen[item.Link] = true
 		merged = append(merged, DecorateRecommendationMedia(item))
 	}
-
-	if len(merged) < min(16, limit) {
-		for _, item := range ranked {
-			if len(merged) >= min(16, limit) || item.Link == "" || seen[item.Link] {
-				continue
-			}
-			if fillerCount >= maxFiller {
-				break
-			}
-			if strings.TrimSpace(item.PreviewVideoURL) == "" && !hasUsableThumbnail(item.ThumbnailURL) {
-				continue
-			}
-			seen[item.Link] = true
-			merged = append(merged, DecorateRecommendationMedia(AIRecommendation{
-				Title:           item.Title,
-				Link:            item.Link,
-				Snippet:         item.Snippet,
-				ThumbnailURL:    item.ThumbnailURL,
-				PreviewVideoURL: item.PreviewVideoURL,
-				Source:          item.Source,
-				Reason:          PendingVisualReason,
-				Recommended:     false,
-			}))
-			fillerCount++
-		}
-	}
 	return merged
 }
 
@@ -489,14 +469,24 @@ func BackfillRecommendations(existing []AIRecommendation, ranked []SearchResult,
 			ThumbnailURL:    item.ThumbnailURL,
 			PreviewVideoURL: item.PreviewVideoURL,
 			Source:          item.Source,
-			Reason:          firstNonEmpty(strings.TrimSpace(reason), FallbackPreviewReason),
+			Reason:          firstNonEmpty(strings.TrimSpace(reason), SupplementalFallbackReason),
 			Recommended:     false,
+			Assessment:      "unclear",
 		}))
 		fillerCount++
 	}
 	return merged
 }
 
+func IsExcludedAssessment(assessment string) bool {
+	switch strings.ToLower(strings.TrimSpace(assessment)) {
+	case "irrelevant", "inappropriate":
+		return true
+	default:
+		return false
+	}
+}
+
 func max(a, b int) int {
 	if a > b {
 		return a