Broaden final recommendation merge

TODO.md

@@ -341,6 +341,17 @@
 - [ ] full browser-level validation was not fully reproducible in this environment
 
 ## Recent Change Log
+- Date: `2026-03-16`
+- What changed:
+  - Relaxed final recommendation merge so Gemini-reviewed non-negative items can still appear, and only a small preview-capable ranked filler set is used when the result list is otherwise too thin.
+- Why it changed:
+  - The stricter `recommended=true only` merge made the visible result set collapse too aggressively in real searches.
+- How it was verified:
+  - `go test ./...`
+  - `bash scripts/selftest.sh`
+- What is still risky or incomplete:
+  - Filler results can still appear with the fallback reason when Gemini-reviewed positives are scarce, though the amount is now intentionally capped.
+
 - Date: `2026-03-16`
 - What changed:
   - Google Video embed URL now uses `youtube-nocookie` with explicit `origin` to reduce player load failures.

backend/services/ranker.go

@@ -302,6 +302,39 @@ func MergeRecommendations(recommended []AIRecommendation, ranked []SearchResult,
 		seen[item.Link] = true
 		merged = append(merged, item)
 	}
+
+	for _, item := range recommended {
+		if item.Recommended || item.Link == "" || seen[item.Link] || len(merged) >= limit {
+			continue
+		}
+		if looksNegativeReason(item.Reason) || strings.Contains(item.Reason, GeminiFallbackReason) {
+			continue
+		}
+		seen[item.Link] = true
+		merged = append(merged, item)
+	}
+
+	if len(merged) < min(6, limit) {
+		for _, item := range ranked {
+			if len(merged) >= min(6, limit) || item.Link == "" || seen[item.Link] {
+				continue
+			}
+			if strings.TrimSpace(item.ThumbnailURL) == "" && strings.TrimSpace(item.PreviewVideoURL) == "" {
+				continue
+			}
+			seen[item.Link] = true
+			merged = append(merged, AIRecommendation{
+				Title:           item.Title,
+				Link:            item.Link,
+				Snippet:         item.Snippet,
+				ThumbnailURL:    item.ThumbnailURL,
+				PreviewVideoURL: item.PreviewVideoURL,
+				Source:          item.Source,
+				Reason:          GeminiFallbackReason,
+				Recommended:     false,
+			})
+		}
+	}
 	return merged
 }