Fallback when Gemini times out without results

TODO.md

@@ -255,6 +255,16 @@
   - backend debug broadcasts
 
 ## Recent Change Log
+- Date: `2026-03-16`
+- What changed:
+  - If Gemini evaluation times out before producing any usable reviewed items, the API now returns a capped ranked fallback set instead of an empty result list.
+- Why it changed:
+  - Users were seeing timeout warnings with no usable results even though ranked candidates already existed.
+- How it was verified:
+  - code-path inspection of timeout fallback branch in `/api/search`
+- What is still risky or incomplete:
+  - Timeout fallback items are still keyword-ranked rather than Gemini-reviewed, so relevance can be lower than a successful full Vision pass.
+
 - Date: `2026-03-16`
 - What changed:
   - Added a search-time budget for Gemini evaluation so the API can return partial reviewed results before reverse-proxy timeout instead of surfacing `504 Gateway Time-out`.

backend/handlers/api.go

@@ -344,6 +344,12 @@ func (a *App) searchMedia(c *gin.Context) {
 			c.JSON(http.StatusOK, gin.H{"results": fallback, "warning": warning, "queries": queryVariants})
 			return
 		}
+		if strings.Contains(warning, "timed out before any usable results were returned") {
+			fallback := services.BuildFallbackRecommendations(scored, 12, "Gemini Vision 시간 제한으로 상위 랭킹 결과를 우선 반환했습니다.")
+			a.debug("search fallback summary", summarizeRecommendationResults(fallback, time.Since(started), warning))
+			c.JSON(http.StatusOK, gin.H{"results": fallback, "warning": warning, "queries": queryVariants})
+			return
+		}
 		a.debug("search fallback summary", summarizeRecommendationResults([]services.AIRecommendation{}, time.Since(started), warning))
 		a.Hub.Broadcast("progress", gin.H{"type": "search", "status": "Gemini Vision returned no usable results", "progress": 90, "message": warning})
 		c.JSON(http.StatusOK, gin.H{"results": []services.AIRecommendation{}, "warning": warning, "queries": queryVariants})