Tolerate Gemini image expansion drift

backend/services/gemini.go

@@ -147,6 +147,11 @@ func (g *GeminiService) ExpandImageQueries(query string) ([]string, error) {
 	}
 	jsonText, err := extractJSONObject(rawText)
 	if err != nil {
+		if looseQueries := parseLooseImageExpansionLines(rawText); len(looseQueries) == 5 {
+			g.setCachedExpansion(cacheKey, looseQueries, 15*time.Minute)
+			g.debug("gemini:image_expand_success", map[string]any{"query": trimmed, "queries": looseQueries, "mode": "loose_text"})
+			return looseQueries, nil
+		}
 		g.debug("gemini:image_expand_parse_error", map[string]any{"query": trimmed, "error": err.Error()})
 		g.setCachedExpansion(cacheKey, fallback, 15*time.Minute)
 		return fallback, err
@@ -801,6 +806,34 @@ func truncateForError(text string, limit int) string {
 	return trimmed[:limit] + "..."
 }
 
+func parseLooseImageExpansionLines(text string) []string {
+	candidates := make([]string, 0, 8)
+	for _, line := range strings.Split(text, "\n") {
+		trimmed := strings.TrimSpace(line)
+		if trimmed == "" {
+			continue
+		}
+		trimmed = strings.TrimPrefix(trimmed, "- ")
+		trimmed = strings.TrimPrefix(trimmed, "* ")
+		trimmed = strings.TrimPrefix(trimmed, "1. ")
+		trimmed = strings.TrimPrefix(trimmed, "2. ")
+		trimmed = strings.TrimPrefix(trimmed, "3. ")
+		trimmed = strings.TrimPrefix(trimmed, "4. ")
+		trimmed = strings.TrimPrefix(trimmed, "5. ")
+		trimmed = strings.TrimSpace(strings.Trim(trimmed, "\"'`"))
+		lower := strings.ToLower(trimmed)
+		if strings.HasPrefix(lower, "here is") || strings.HasPrefix(lower, "json") || strings.HasPrefix(lower, "output") {
+			continue
+		}
+		candidates = append(candidates, trimmed)
+	}
+	queries := normalizeImageExpansionQueries(candidates)
+	if len(queries) < 5 {
+		return nil
+	}
+	return queries[:5]
+}
+
 func normalizeKoreanReason(reason string) string {
 	trimmed := strings.TrimSpace(reason)
 	if trimmed == "" {